From 07e569877035b1d2490684c92ad9794c865dca76 Mon Sep 17 00:00:00 2001
From: Ilian Pihlajamaa <ilian.pihlajamaa@gmail.com>
Date: Mon, 11 Sep 2023 17:18:20 +0200
Subject: [PATCH 01/15] add IntegralDataProblem

---
 src/SciMLBase.jl               |  2 +-
 src/problems/basic_problems.jl | 53 ++++++++++++++++++++++++++++++++++
 2 files changed, 54 insertions(+), 1 deletion(-)

diff --git a/src/SciMLBase.jl b/src/SciMLBase.jl
index e4d1e371f..b583be5ab 100644
--- a/src/SciMLBase.jl
+++ b/src/SciMLBase.jl
@@ -762,7 +762,7 @@ export LinearProblem,
     NonlinearProblem, IntervalNonlinearProblem,
     IntegralProblem, OptimizationProblem
 
-export IntegralProblem
+export IntegralDataProblem
 
 export DiscreteProblem, ImplicitDiscreteProblem
 export SteadyStateProblem, SteadyStateSolution
diff --git a/src/problems/basic_problems.jl b/src/problems/basic_problems.jl
index 6cb329290..90f5bfefa 100644
--- a/src/problems/basic_problems.jl
+++ b/src/problems/basic_problems.jl
@@ -386,6 +386,59 @@ function IntegralProblem(f, lb, ub, args...; kwargs...)
     IntegralProblem{isinplace(f, 3)}(f, lb, ub, args...; kwargs...)
 end
 
+@doc doc"""
+
+Defines a sampled integral problem.
+Documentation Page: https://docs.sciml.ai/Integrals/stable/
+
+## Mathematical Specification of a Sampled Integral Problem
+
+Integral problems define integrals over a set of data `y`
+with corresponding sampling points `x`. 
+
+`y` is an `AbstractArray` and `x` is a `AbstractVector`,
+whose elements define the space being integrated along the dimension of `y` that is integrated.
+This dimension is given by `dim`.
+
+## Problem Type
+
+### Constructors
+
+IntegralProblem(y,x;
+                  dim=1, kwargs...)
+
+- `y`: The integrand
+- `x`: The sampled integration domain
+- `dim`: The dimension of `y`being integrated
+- kwargs: Keyword arguments copied to the solvers.
+
+### Fields
+
+The fields match the names of the constructor arguments.
+"""
+struct IntegralDataProblem{Y<:AbstractArray, X<:AbstractVector, DIMVAL} <: AbstractIntegralProblem{false}
+    x::X
+    y::Y
+    dim::DIMVAL
+    kwargs::K
+    @add_kwonly function IntegralProblem(x, y;
+        dim = 1,
+        kwargs...) 
+        @assert length(x) > 1
+        @assert isfinite(first(x)) "Infinite limits are not supported"
+        @assert isfinite(last(x)) "Infinite limits are not supported"
+        @assert size(y, dim) == length(x) "Integrand and grid must be of equal length along the integrated dimension"
+        @assert axes(y, dim) == axes(x,1) "Grid and integrand array must use the same indexing along integrated dimension" 
+        new{typeof(x), typeof(y), Val{dim}, typeof(kwargs)}(x, y, Val(dim), kwargs)
+    end
+end
+
+TruncatedStacktraces.@truncate_stacktrace IntegralDataProblem 1 4
+
+function IntegralProblem(x::AbstractArray, y::AbstractVector; dim=1, kwargs...)
+    IntegralDataProblem(x, y; dim=dim)
+end
+
 struct QuadratureProblem end
 @deprecate QuadratureProblem(args...; kwargs...) IntegralProblem(args...; kwargs...)
 

From 181847d4c6a7d639ca4e51b3fe7291630914c026 Mon Sep 17 00:00:00 2001
From: Ilian Pihlajamaa <ilian.pihlajamaa@gmail.com>
Date: Mon, 11 Sep 2023 17:55:06 +0200
Subject: [PATCH 02/15] fix mistake

---
 src/problems/basic_problems.jl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/problems/basic_problems.jl b/src/problems/basic_problems.jl
index 90f5bfefa..dd94f21a0 100644
--- a/src/problems/basic_problems.jl
+++ b/src/problems/basic_problems.jl
@@ -416,7 +416,7 @@ IntegralProblem(y,x;
 
 The fields match the names of the constructor arguments.
 """
-struct IntegralDataProblem{Y<:AbstractArray, X<:AbstractVector, DIMVAL} <: AbstractIntegralProblem{false}
+struct IntegralDataProblem{Y<:AbstractArray, X<:AbstractVector, DIMVAL, K} <: AbstractIntegralProblem{false}
     x::X
     y::Y
     dim::DIMVAL

From 2fcfbb549097ecd446304b127b4e0cb032b135b7 Mon Sep 17 00:00:00 2001
From: Ilian Pihlajamaa <ilian.pihlajamaa@gmail.com>
Date: Mon, 11 Sep 2023 18:05:13 +0200
Subject: [PATCH 03/15] another small mistake

---
 src/problems/basic_problems.jl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/problems/basic_problems.jl b/src/problems/basic_problems.jl
index dd94f21a0..24b955965 100644
--- a/src/problems/basic_problems.jl
+++ b/src/problems/basic_problems.jl
@@ -421,7 +421,7 @@ struct IntegralDataProblem{Y<:AbstractArray, X<:AbstractVector, DIMVAL, K} <: Ab
     y::Y
     dim::DIMVAL
     kwargs::K
-    @add_kwonly function IntegralProblem(x, y;
+    @add_kwonly function IntegralDataProblem(x, y;
         dim = 1,
         kwargs...) 
         @assert length(x) > 1

From dfd917a38c9dd3d4acec6c804932e6601752ebee Mon Sep 17 00:00:00 2001
From: Ilian Pihlajamaa <ilian.pihlajamaa@gmail.com>
Date: Wed, 13 Sep 2023 09:44:32 +0200
Subject: [PATCH 04/15] removed `IntegralDataProblem`, added x and dim field to
 `IntegralProblem`

---
 src/problems/basic_problems.jl | 85 ++++++++++++----------------------
 1 file changed, 29 insertions(+), 56 deletions(-)

diff --git a/src/problems/basic_problems.jl b/src/problems/basic_problems.jl
index 24b955965..877320ae5 100644
--- a/src/problems/basic_problems.jl
+++ b/src/problems/basic_problems.jl
@@ -334,10 +334,16 @@ which are `Number`s or `AbstractVector`s with the same geometry as `u`.
 
 ### Constructors
 
+```
 IntegralProblem{iip}(f,lb,ub,p=NullParameters();
                   nout=1, batch = 0, kwargs...)
 
-- f: the integrand, `y = f(u,p)` for out-of-place or `f(y,u,p)` for in-place.
+IntegralProblem{iip}(f, x::AbstractVector{<:Number}, p = NullParameters();
+                  nout = 1,
+                  batch = 0, kwargs...)
+```
+
+- f: the integrand, callable function `y = f(u,p)` for out-of-place or `f(y,u,p)` for in-place, or `AbstractArray` for sampled problems.
 - lb: Either a number or vector of lower bounds.
 - ub: Either a number or vector of upper bounds.
 - p: The parameters associated with the problem.
@@ -353,6 +359,8 @@ IntegralProblem{iip}(f,lb,ub,p=NullParameters();
   if `f` is a scalar valued function `y[i]` is the evaluation of `f` at a different point.
   Note that batch is a suggestion for the number of points,
   and it is not necessarily true that batch is the same as batchsize in all algorithms.
+- x: Vector of gridpoints on which to evaluate the integrand for integrators that support this. Defaults to `nothing`
+- dim: For integrals over sampled data (when `f isa AbstractArray`), this specifies the dimension along which is integrated.
 - kwargs: Keyword arguments copied to the solvers.
 
 Additionally, we can supply iip like IntegralProblem{iip}(...) as true or false to declare at
@@ -362,21 +370,33 @@ compile time whether the integrator function is in-place.
 
 The fields match the names of the constructor arguments.
 """
-struct IntegralProblem{isinplace, P, F, B, K} <: AbstractIntegralProblem{isinplace}
+struct IntegralProblem{isinplace, P, F, B, K, X, D} <: AbstractIntegralProblem{isinplace}
     f::F
     lb::B
     ub::B
     nout::Int
     p::P
     batch::Int
+    x::X
+    dim::D
     kwargs::K
     @add_kwonly function IntegralProblem{iip}(f, lb, ub, p = NullParameters();
         nout = 1,
-        batch = 0, kwargs...) where {iip}
+        batch = 0, x=nothing, dim=Val(1), kwargs...) where {iip}
         @assert typeof(lb)==typeof(ub) "Type of lower and upper bound must match"
         warn_paramtype(p)
-        new{iip, typeof(p), typeof(f), typeof(lb), typeof(kwargs)}(f, lb, ub, nout, p,
-            batch, kwargs)
+        new{iip, typeof(p), typeof(f), typeof(lb), typeof(x), typeof(dim) typeof(kwargs)}(f, lb, ub, nout, p,
+            batch, x, dim, kwargs)
+    end
+    @add_kwonly function IntegralProblem{iip}(f, x::AbstractVector{<:Number}, p = NullParameters();
+        dim=Val(1),
+        nout = 1,
+        batch = 0, kwargs...) where {iip}
+        lb = x[begin]
+        ub = x[end]
+        warn_paramtype(p)
+        new{iip, typeof(p), typeof(f), typeof(lb), typeof(x), typeof(dim), typeof(kwargs)}(f, lb, ub, nout, p,
+            batch, x, dim, kwargs)
     end
 end
 
@@ -385,58 +405,11 @@ TruncatedStacktraces.@truncate_stacktrace IntegralProblem 1 4
 function IntegralProblem(f, lb, ub, args...; kwargs...)
     IntegralProblem{isinplace(f, 3)}(f, lb, ub, args...; kwargs...)
 end
-
-@doc doc"""
-
-Defines a sampled integral problem.
-Documentation Page: https://docs.sciml.ai/Integrals/stable/
-
-## Mathematical Specification of a Sampled Integral Problem
-
-Integral problems define integrals over a set of data `y`
-with corresponding sampling points `x`. 
-
-`y` is an `AbstractArray` and `x` is a `AbstractVector`,
-whose elements define the space being integrated along the dimension of `y` that is integrated.
-This dimension is given by `dim`.
-
-## Problem Type
-
-### Constructors
-
-IntegralProblem(y,x;
-                  dim=1, kwargs...)
-
-- `y`: The integrand
-- `x`: The sampled integration domain
-- `dim`: The dimension of `y`being integrated
-- kwargs: Keyword arguments copied to the solvers.
-
-### Fields
-
-The fields match the names of the constructor arguments.
-"""
-struct IntegralDataProblem{Y<:AbstractArray, X<:AbstractVector, DIMVAL, K} <: AbstractIntegralProblem{false}
-    x::X
-    y::Y
-    dim::DIMVAL
-    kwargs::K
-    @add_kwonly function IntegralDataProblem(x, y;
-        dim = 1,
-        kwargs...) 
-        @assert length(x) > 1
-        @assert isfinite(first(x)) "Infinite limits are not supported"
-        @assert isfinite(last(x)) "Infinite limits are not supported"
-        @assert size(y, dim) == length(x) "Integrand and grid must be of equal length along the integrated dimension"
-        @assert axes(y, dim) == axes(x,1) "Grid and integrand array must use the same indexing along integrated dimension" 
-        new{typeof(x), typeof(y), Val{dim}, typeof(kwargs)}(x, y, Val(dim), kwargs)
-    end
+function IntegralProblem(f, x::AbstractVector{<:Number}, args...; kwargs...)
+    IntegralProblem{isinplace(f, 3)}(f, x, args...; kwargs...)
 end
-
-TruncatedStacktraces.@truncate_stacktrace IntegralDataProblem 1 4
-
-function IntegralProblem(x::AbstractArray, y::AbstractVector; dim=1, kwargs...)
-    IntegralDataProblem(x, y; dim=dim)
+function IntegralProblem(y::AbstractArray, x::AbstractVector{<:Number}, args...; dim::Int=1, kwargs...)
+    IntegralProblem{false}(y, x, args...; dim=Val(dim), kwargs...)
 end
 
 struct QuadratureProblem end

From e60e921f5e7f2e538bbb6cc70275a41b492096ed Mon Sep 17 00:00:00 2001
From: Ilian Pihlajamaa <ilian.pihlajamaa@gmail.com>
Date: Wed, 13 Sep 2023 09:45:37 +0200
Subject: [PATCH 05/15] Stop exporting IntegralDataProblem

---
 src/SciMLBase.jl | 2 --
 1 file changed, 2 deletions(-)

diff --git a/src/SciMLBase.jl b/src/SciMLBase.jl
index b583be5ab..f52d73b2c 100644
--- a/src/SciMLBase.jl
+++ b/src/SciMLBase.jl
@@ -762,8 +762,6 @@ export LinearProblem,
     NonlinearProblem, IntervalNonlinearProblem,
     IntegralProblem, OptimizationProblem
 
-export IntegralDataProblem
-
 export DiscreteProblem, ImplicitDiscreteProblem
 export SteadyStateProblem, SteadyStateSolution
 export NoiseProblem

From a92e7f701ebd2814f2bcb1a4efdafb6d202abd5e Mon Sep 17 00:00:00 2001
From: Ilian Pihlajamaa <ilian.pihlajamaa@gmail.com>
Date: Thu, 14 Sep 2023 14:18:50 +0200
Subject: [PATCH 06/15] fix typo in IntegralProblem

---
 src/problems/basic_problems.jl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/problems/basic_problems.jl b/src/problems/basic_problems.jl
index 877320ae5..cc106f3ec 100644
--- a/src/problems/basic_problems.jl
+++ b/src/problems/basic_problems.jl
@@ -385,7 +385,7 @@ struct IntegralProblem{isinplace, P, F, B, K, X, D} <: AbstractIntegralProblem{i
         batch = 0, x=nothing, dim=Val(1), kwargs...) where {iip}
         @assert typeof(lb)==typeof(ub) "Type of lower and upper bound must match"
         warn_paramtype(p)
-        new{iip, typeof(p), typeof(f), typeof(lb), typeof(x), typeof(dim) typeof(kwargs)}(f, lb, ub, nout, p,
+        new{iip, typeof(p), typeof(f), typeof(lb), typeof(x), typeof(dim), typeof(kwargs)}(f, lb, ub, nout, p,
             batch, x, dim, kwargs)
     end
     @add_kwonly function IntegralProblem{iip}(f, x::AbstractVector{<:Number}, p = NullParameters();

From af4cfb8e328f6b60420d26fb24ba50697901c47a Mon Sep 17 00:00:00 2001
From: Ilian Pihlajamaa <ilian.pihlajamaa@gmail.com>
Date: Thu, 14 Sep 2023 14:51:51 +0200
Subject: [PATCH 07/15] removed one unnecessary inner constructor

---
 src/problems/basic_problems.jl | 18 ++++--------------
 1 file changed, 4 insertions(+), 14 deletions(-)

diff --git a/src/problems/basic_problems.jl b/src/problems/basic_problems.jl
index cc106f3ec..7fe5a58fc 100644
--- a/src/problems/basic_problems.jl
+++ b/src/problems/basic_problems.jl
@@ -370,7 +370,7 @@ compile time whether the integrator function is in-place.
 
 The fields match the names of the constructor arguments.
 """
-struct IntegralProblem{isinplace, P, F, B, K, X, D} <: AbstractIntegralProblem{isinplace}
+struct IntegralProblem{isinplace, P, F, B, X, D, K} <: AbstractIntegralProblem{isinplace}
     f::F
     lb::B
     ub::B
@@ -382,22 +382,12 @@ struct IntegralProblem{isinplace, P, F, B, K, X, D} <: AbstractIntegralProblem{i
     kwargs::K
     @add_kwonly function IntegralProblem{iip}(f, lb, ub, p = NullParameters();
         nout = 1,
-        batch = 0, x=nothing, dim=Val(1), kwargs...) where {iip}
+        batch = 0, x=nothing, dim=nothing, kwargs...) where {iip}
         @assert typeof(lb)==typeof(ub) "Type of lower and upper bound must match"
         warn_paramtype(p)
         new{iip, typeof(p), typeof(f), typeof(lb), typeof(x), typeof(dim), typeof(kwargs)}(f, lb, ub, nout, p,
             batch, x, dim, kwargs)
     end
-    @add_kwonly function IntegralProblem{iip}(f, x::AbstractVector{<:Number}, p = NullParameters();
-        dim=Val(1),
-        nout = 1,
-        batch = 0, kwargs...) where {iip}
-        lb = x[begin]
-        ub = x[end]
-        warn_paramtype(p)
-        new{iip, typeof(p), typeof(f), typeof(lb), typeof(x), typeof(dim), typeof(kwargs)}(f, lb, ub, nout, p,
-            batch, x, dim, kwargs)
-    end
 end
 
 TruncatedStacktraces.@truncate_stacktrace IntegralProblem 1 4
@@ -406,10 +396,10 @@ function IntegralProblem(f, lb, ub, args...; kwargs...)
     IntegralProblem{isinplace(f, 3)}(f, lb, ub, args...; kwargs...)
 end
 function IntegralProblem(f, x::AbstractVector{<:Number}, args...; kwargs...)
-    IntegralProblem{isinplace(f, 3)}(f, x, args...; kwargs...)
+    IntegralProblem(f, x[begin], x[end], args...; x=x, kwargs...)
 end
 function IntegralProblem(y::AbstractArray, x::AbstractVector{<:Number}, args...; dim::Int=1, kwargs...)
-    IntegralProblem{false}(y, x, args...; dim=Val(dim), kwargs...)
+    IntegralProblem{false}(y, x[begin], x[end], args...; dim=Val(dim), kwargs...)
 end
 
 struct QuadratureProblem end

From caedc7c5ad772a510ae23842420ec0262ad4176d Mon Sep 17 00:00:00 2001
From: Ilian Pihlajamaa <ilian.pihlajamaa@gmail.com>
Date: Fri, 15 Sep 2023 09:43:35 +0200
Subject: [PATCH 08/15] remove method ambiguity

---
 src/problems/basic_problems.jl           | 5 ++++-
 test/function_building_error_messages.jl | 1 +
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/problems/basic_problems.jl b/src/problems/basic_problems.jl
index 7fe5a58fc..1fde2ced6 100644
--- a/src/problems/basic_problems.jl
+++ b/src/problems/basic_problems.jl
@@ -392,7 +392,10 @@ end
 
 TruncatedStacktraces.@truncate_stacktrace IntegralProblem 1 4
 
-function IntegralProblem(f, lb, ub, args...; kwargs...)
+function IntegralProblem(f, lb::AbstractVector{<:Number}, ub::AbstractVector{<:Number}, args...; kwargs...)
+    IntegralProblem{isinplace(f, 3)}(f, lb, ub, args...; kwargs...)
+end
+function IntegralProblem(f, lb::Number, ub::Number, args...; kwargs...)
     IntegralProblem{isinplace(f, 3)}(f, lb, ub, args...; kwargs...)
 end
 function IntegralProblem(f, x::AbstractVector{<:Number}, args...; kwargs...)
diff --git a/test/function_building_error_messages.jl b/test/function_building_error_messages.jl
index a150371d8..8a1dbdf47 100644
--- a/test/function_building_error_messages.jl
+++ b/test/function_building_error_messages.jl
@@ -455,6 +455,7 @@ intf(u) = 1.0
 intf(u, p) = 1.0
 IntegralProblem(intf, 0.0, 1.0)
 
+
 # Optimization
 
 optf(u) = 1.0

From 7cee282d8fc3a5c21638f2e1613c5db53a976e48 Mon Sep 17 00:00:00 2001
From: Ilian Pihlajamaa <ilian.pihlajamaa@gmail.com>
Date: Fri, 15 Sep 2023 09:48:19 +0200
Subject: [PATCH 09/15] add problem building tests

---
 test/function_building_error_messages.jl | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/test/function_building_error_messages.jl b/test/function_building_error_messages.jl
index 8a1dbdf47..ab8ddcbc4 100644
--- a/test/function_building_error_messages.jl
+++ b/test/function_building_error_messages.jl
@@ -453,8 +453,17 @@ NonlinearFunction(nfoop, vjp = nvjp)
 intf(u) = 1.0
 @test_throws SciMLBase.TooFewArgumentsError IntegralProblem(intf, 0.0, 1.0)
 intf(u, p) = 1.0
+p = 2.0
+x =  [1.0,2.0]
+y = rand(2,2)
 IntegralProblem(intf, 0.0, 1.0)
-
+IntegralProblem(intf, 0.0, 1.0, p) 
+IntegralProblem(intf, [0.0], [1.0])
+IntegralProblem(intf, [0.0], [1.0], p)
+IntegralProblem(intf, x)
+IntegralProblem(intf, x, p)
+IntegralProblem(y, x)
+IntegralProblem(y, x, p)
 
 # Optimization
 

From 6b21a0d8b29e1013319ad9f2b3fa7457a4b7a4cd Mon Sep 17 00:00:00 2001
From: Ilian Pihlajamaa <ilian.pihlajamaa@gmail.com>
Date: Fri, 15 Sep 2023 09:58:47 +0200
Subject: [PATCH 10/15] ran the format_document.jl thing in VScode

---
 src/problems/basic_problems.jl           | 21 +++++++++++++++------
 test/function_building_error_messages.jl |  6 +++---
 2 files changed, 18 insertions(+), 9 deletions(-)

diff --git a/src/problems/basic_problems.jl b/src/problems/basic_problems.jl
index 1fde2ced6..3cf8bb819 100644
--- a/src/problems/basic_problems.jl
+++ b/src/problems/basic_problems.jl
@@ -382,27 +382,36 @@ struct IntegralProblem{isinplace, P, F, B, X, D, K} <: AbstractIntegralProblem{i
     kwargs::K
     @add_kwonly function IntegralProblem{iip}(f, lb, ub, p = NullParameters();
         nout = 1,
-        batch = 0, x=nothing, dim=nothing, kwargs...) where {iip}
+        batch = 0, x = nothing, dim = nothing, kwargs...) where {iip}
         @assert typeof(lb)==typeof(ub) "Type of lower and upper bound must match"
         warn_paramtype(p)
-        new{iip, typeof(p), typeof(f), typeof(lb), typeof(x), typeof(dim), typeof(kwargs)}(f, lb, ub, nout, p,
+        new{iip, typeof(p), typeof(f), typeof(lb), typeof(x), typeof(dim), typeof(kwargs)}(f,
+            lb, ub, nout, p,
             batch, x, dim, kwargs)
     end
 end
 
 TruncatedStacktraces.@truncate_stacktrace IntegralProblem 1 4
 
-function IntegralProblem(f, lb::AbstractVector{<:Number}, ub::AbstractVector{<:Number}, args...; kwargs...)
+function IntegralProblem(f,
+    lb::AbstractVector{<:Number},
+    ub::AbstractVector{<:Number},
+    args...;
+    kwargs...)
     IntegralProblem{isinplace(f, 3)}(f, lb, ub, args...; kwargs...)
 end
 function IntegralProblem(f, lb::Number, ub::Number, args...; kwargs...)
     IntegralProblem{isinplace(f, 3)}(f, lb, ub, args...; kwargs...)
 end
 function IntegralProblem(f, x::AbstractVector{<:Number}, args...; kwargs...)
-    IntegralProblem(f, x[begin], x[end], args...; x=x, kwargs...)
+    IntegralProblem(f, x[begin], x[end], args...; x = x, kwargs...)
 end
-function IntegralProblem(y::AbstractArray, x::AbstractVector{<:Number}, args...; dim::Int=1, kwargs...)
-    IntegralProblem{false}(y, x[begin], x[end], args...; dim=Val(dim), kwargs...)
+function IntegralProblem(y::AbstractArray,
+    x::AbstractVector{<:Number},
+    args...;
+    dim::Int = 1,
+    kwargs...)
+    IntegralProblem{false}(y, x[begin], x[end], args...; dim = Val(dim), kwargs...)
 end
 
 struct QuadratureProblem end
diff --git a/test/function_building_error_messages.jl b/test/function_building_error_messages.jl
index ab8ddcbc4..3a7b339d7 100644
--- a/test/function_building_error_messages.jl
+++ b/test/function_building_error_messages.jl
@@ -454,10 +454,10 @@ intf(u) = 1.0
 @test_throws SciMLBase.TooFewArgumentsError IntegralProblem(intf, 0.0, 1.0)
 intf(u, p) = 1.0
 p = 2.0
-x =  [1.0,2.0]
-y = rand(2,2)
+x = [1.0, 2.0]
+y = rand(2, 2)
 IntegralProblem(intf, 0.0, 1.0)
-IntegralProblem(intf, 0.0, 1.0, p) 
+IntegralProblem(intf, 0.0, 1.0, p)
 IntegralProblem(intf, [0.0], [1.0])
 IntegralProblem(intf, [0.0], [1.0], p)
 IntegralProblem(intf, x)

From 09561b62e56c39a89b5dea18a5b86d404d6fb5e5 Mon Sep 17 00:00:00 2001
From: Ilian Pihlajamaa <ilian.pihlajamaa@gmail.com>
Date: Fri, 15 Sep 2023 11:33:42 +0200
Subject: [PATCH 11/15] Update basic_problems.jl

---
 src/problems/basic_problems.jl | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/src/problems/basic_problems.jl b/src/problems/basic_problems.jl
index 3cf8bb819..63ad114e0 100644
--- a/src/problems/basic_problems.jl
+++ b/src/problems/basic_problems.jl
@@ -393,17 +393,24 @@ end
 
 TruncatedStacktraces.@truncate_stacktrace IntegralProblem 1 4
 
-function IntegralProblem(f,
+function IntegralProblem(f::Function,
     lb::AbstractVector{<:Number},
     ub::AbstractVector{<:Number},
     args...;
     kwargs...)
     IntegralProblem{isinplace(f, 3)}(f, lb, ub, args...; kwargs...)
 end
-function IntegralProblem(f, lb::Number, ub::Number, args...; kwargs...)
+function IntegralProblem(f::Function,
+    lb::Number,
+    ub::Number,
+    args...;
+    kwargs...)
     IntegralProblem{isinplace(f, 3)}(f, lb, ub, args...; kwargs...)
 end
-function IntegralProblem(f, x::AbstractVector{<:Number}, args...; kwargs...)
+function IntegralProblem(f::Function,
+    x::AbstractVector{<:Number},
+    args...;
+    kwargs...)
     IntegralProblem(f, x[begin], x[end], args...; x = x, kwargs...)
 end
 function IntegralProblem(y::AbstractArray,
@@ -411,7 +418,7 @@ function IntegralProblem(y::AbstractArray,
     args...;
     dim::Int = 1,
     kwargs...)
-    IntegralProblem{false}(y, x[begin], x[end], args...; dim = Val(dim), kwargs...)
+    IntegralProblem{false}(y, x[begin], x[end], p = nothing; dim = Val(dim), kwargs...)
 end
 
 struct QuadratureProblem end

From cdc36635707177d6118aa560c4823ba6faa658b8 Mon Sep 17 00:00:00 2001
From: IlianPihlajamaa <73794090+IlianPihlajamaa@users.noreply.github.com>
Date: Sat, 16 Sep 2023 21:52:03 +0200
Subject: [PATCH 12/15] revert to DataIntegralProblem

---
 src/SciMLBase.jl                         |  2 +-
 src/problems/basic_problems.jl           | 92 ++++++++++++++----------
 test/function_building_error_messages.jl | 12 ++--
 3 files changed, 62 insertions(+), 44 deletions(-)

diff --git a/src/SciMLBase.jl b/src/SciMLBase.jl
index f52d73b2c..1de4703d6 100644
--- a/src/SciMLBase.jl
+++ b/src/SciMLBase.jl
@@ -760,7 +760,7 @@ export solve, solve!, init, discretize, symbolic_discretize
 
 export LinearProblem,
     NonlinearProblem, IntervalNonlinearProblem,
-    IntegralProblem, OptimizationProblem
+    IntegralProblem, DataIntegralProblem, OptimizationProblem
 
 export DiscreteProblem, ImplicitDiscreteProblem
 export SteadyStateProblem, SteadyStateSolution
diff --git a/src/problems/basic_problems.jl b/src/problems/basic_problems.jl
index 63ad114e0..f794b0e16 100644
--- a/src/problems/basic_problems.jl
+++ b/src/problems/basic_problems.jl
@@ -337,13 +337,9 @@ which are `Number`s or `AbstractVector`s with the same geometry as `u`.
 ```
 IntegralProblem{iip}(f,lb,ub,p=NullParameters();
                   nout=1, batch = 0, kwargs...)
-
-IntegralProblem{iip}(f, x::AbstractVector{<:Number}, p = NullParameters();
-                  nout = 1,
-                  batch = 0, kwargs...)
 ```
 
-- f: the integrand, callable function `y = f(u,p)` for out-of-place or `f(y,u,p)` for in-place, or `AbstractArray` for sampled problems.
+- f: the integrand, callable function `y = f(u,p)` for out-of-place or `f(y,u,p)` for in-place.
 - lb: Either a number or vector of lower bounds.
 - ub: Either a number or vector of upper bounds.
 - p: The parameters associated with the problem.
@@ -359,8 +355,6 @@ IntegralProblem{iip}(f, x::AbstractVector{<:Number}, p = NullParameters();
   if `f` is a scalar valued function `y[i]` is the evaluation of `f` at a different point.
   Note that batch is a suggestion for the number of points,
   and it is not necessarily true that batch is the same as batchsize in all algorithms.
-- x: Vector of gridpoints on which to evaluate the integrand for integrators that support this. Defaults to `nothing`
-- dim: For integrals over sampled data (when `f isa AbstractArray`), this specifies the dimension along which is integrated.
 - kwargs: Keyword arguments copied to the solvers.
 
 Additionally, we can supply iip like IntegralProblem{iip}(...) as true or false to declare at
@@ -370,62 +364,86 @@ compile time whether the integrator function is in-place.
 
 The fields match the names of the constructor arguments.
 """
-struct IntegralProblem{isinplace, P, F, B, X, D, K} <: AbstractIntegralProblem{isinplace}
+struct IntegralProblem{isinplace, P, F, B, K} <: AbstractIntegralProblem{isinplace}
     f::F
     lb::B
     ub::B
     nout::Int
     p::P
     batch::Int
-    x::X
-    dim::D
     kwargs::K
     @add_kwonly function IntegralProblem{iip}(f, lb, ub, p = NullParameters();
         nout = 1,
-        batch = 0, x = nothing, dim = nothing, kwargs...) where {iip}
+        batch = 0, kwargs...) where {iip}
         @assert typeof(lb)==typeof(ub) "Type of lower and upper bound must match"
         warn_paramtype(p)
-        new{iip, typeof(p), typeof(f), typeof(lb), typeof(x), typeof(dim), typeof(kwargs)}(f,
+        new{iip, typeof(p), typeof(f), typeof(lb), typeof(kwargs)}(f,
             lb, ub, nout, p,
-            batch, x, dim, kwargs)
+            batch, kwargs)
     end
 end
 
 TruncatedStacktraces.@truncate_stacktrace IntegralProblem 1 4
 
-function IntegralProblem(f::Function,
-    lb::AbstractVector{<:Number},
-    ub::AbstractVector{<:Number},
-    args...;
-    kwargs...)
-    IntegralProblem{isinplace(f, 3)}(f, lb, ub, args...; kwargs...)
-end
-function IntegralProblem(f::Function,
-    lb::Number,
-    ub::Number,
-    args...;
+function IntegralProblem(f, lb, ub, args...;
     kwargs...)
     IntegralProblem{isinplace(f, 3)}(f, lb, ub, args...; kwargs...)
 end
-function IntegralProblem(f::Function,
-    x::AbstractVector{<:Number},
-    args...;
-    kwargs...)
-    IntegralProblem(f, x[begin], x[end], args...; x = x, kwargs...)
-end
-function IntegralProblem(y::AbstractArray,
-    x::AbstractVector{<:Number},
-    args...;
-    dim::Int = 1,
-    kwargs...)
-    IntegralProblem{false}(y, x[begin], x[end], p = nothing; dim = Val(dim), kwargs...)
-end
 
 struct QuadratureProblem end
 @deprecate QuadratureProblem(args...; kwargs...) IntegralProblem(args...; kwargs...)
 
 @doc doc"""
 
+Defines a integral problem over pre-sampled data.
+Documentation Page: https://docs.sciml.ai/Integrals/stable/
+
+## Mathematical Specification of a data Integral Problem
+
+Data integral problems are defined as:
+
+```math
+\sum_i w_i y_i
+```
+where `y_i` are sampled values of the integrand, and `w_i` are weights 
+assigned by a quadrature rule, which depend on sampling points `x`. 
+
+## Problem Type
+
+### Constructors
+
+```
+DataIntegralProblem(x::AbstractVector, y::AbstractArray; dim=1, kwargs...)
+```
+- y: The sampled integrand, must be a subtype of `AbstractArray`. 
+  It is assumed that the values of `y` along dimension `dim` 
+  correspond to the integrand evaluated at sampling points `x`
+- x: Sampling points, must be a subtype of `AbstractVector`.   
+- dim: Dimension along which to integrate.
+- kwargs: Keyword arguments copied to the solvers.
+
+### Fields
+
+The fields match the names of the constructor arguments.
+"""
+struct DataIntegralProblem{Y, X, D, K} <: AbstractIntegralProblem{false}
+    y::Y
+    x::X
+    dim::D
+    kwargs::K
+    @add_kwonly function DataIntegralProblem(y::AbstractArray, x::AbstractVector;
+        dim = 1,
+        kwargs...)
+        @assert length(x)==size(y, dim) "The integrand `y` must have the same length as the sampling points `x` along the integrated dimension."
+        @assert axes(x, 1)==axes(y, dim) "The integrand `y` must obey the same indexing as the sampling points `x` along the integrated dimension."
+        new{typeof(y), typeof(x), Val{dim}, typeof(kwargs)}(y, x, Val(dim), kwargs)
+    end
+end
+
+TruncatedStacktraces.@truncate_stacktrace DataIntegralProblem 1 4
+
+@doc doc"""
+
 Defines an optimization problem.
 Documentation Page: https://docs.sciml.ai/Optimization/stable/API/optimization_problem/
 
diff --git a/test/function_building_error_messages.jl b/test/function_building_error_messages.jl
index 3a7b339d7..8fffc806b 100644
--- a/test/function_building_error_messages.jl
+++ b/test/function_building_error_messages.jl
@@ -454,16 +454,16 @@ intf(u) = 1.0
 @test_throws SciMLBase.TooFewArgumentsError IntegralProblem(intf, 0.0, 1.0)
 intf(u, p) = 1.0
 p = 2.0
-x = [1.0, 2.0]
-y = rand(2, 2)
+
 IntegralProblem(intf, 0.0, 1.0)
 IntegralProblem(intf, 0.0, 1.0, p)
 IntegralProblem(intf, [0.0], [1.0])
 IntegralProblem(intf, [0.0], [1.0], p)
-IntegralProblem(intf, x)
-IntegralProblem(intf, x, p)
-IntegralProblem(y, x)
-IntegralProblem(y, x, p)
+
+x = [1.0, 2.0]
+y = rand(2, 2)
+DataIntegralProblem(y, x)
+DataIntegralProblem(y, x; dim=2)
 
 # Optimization
 

From d3619dba982275026aa1b0e91ecc3b627cd0599b Mon Sep 17 00:00:00 2001
From: IlianPihlajamaa <73794090+IlianPihlajamaa@users.noreply.github.com>
Date: Sat, 16 Sep 2023 21:57:18 +0200
Subject: [PATCH 13/15] add additional assert

---
 src/problems/basic_problems.jl | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/problems/basic_problems.jl b/src/problems/basic_problems.jl
index f794b0e16..b2caeabe9 100644
--- a/src/problems/basic_problems.jl
+++ b/src/problems/basic_problems.jl
@@ -434,6 +434,7 @@ struct DataIntegralProblem{Y, X, D, K} <: AbstractIntegralProblem{false}
     @add_kwonly function DataIntegralProblem(y::AbstractArray, x::AbstractVector;
         dim = 1,
         kwargs...)
+        @assert dim <= ndims(y) "The integration dimension `dim` is larger than the number of dimensions of the integrand `y`"
         @assert length(x)==size(y, dim) "The integrand `y` must have the same length as the sampling points `x` along the integrated dimension."
         @assert axes(x, 1)==axes(y, dim) "The integrand `y` must obey the same indexing as the sampling points `x` along the integrated dimension."
         new{typeof(y), typeof(x), Val{dim}, typeof(kwargs)}(y, x, Val(dim), kwargs)

From 124d3bec83466215bab456c3106e94be25e07481 Mon Sep 17 00:00:00 2001
From: IlianPihlajamaa <73794090+IlianPihlajamaa@users.noreply.github.com>
Date: Sat, 16 Sep 2023 22:45:01 +0200
Subject: [PATCH 14/15] rename `DataIntegralProblem` to
 `SampledIntegralProblem`

---
 src/SciMLBase.jl                         |  2 +-
 src/problems/basic_problems.jl           | 10 +++++-----
 test/function_building_error_messages.jl |  4 ++--
 3 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/src/SciMLBase.jl b/src/SciMLBase.jl
index 1de4703d6..f0811160f 100644
--- a/src/SciMLBase.jl
+++ b/src/SciMLBase.jl
@@ -760,7 +760,7 @@ export solve, solve!, init, discretize, symbolic_discretize
 
 export LinearProblem,
     NonlinearProblem, IntervalNonlinearProblem,
-    IntegralProblem, DataIntegralProblem, OptimizationProblem
+    IntegralProblem, SampledIntegralProblem, OptimizationProblem
 
 export DiscreteProblem, ImplicitDiscreteProblem
 export SteadyStateProblem, SteadyStateSolution
diff --git a/src/problems/basic_problems.jl b/src/problems/basic_problems.jl
index b2caeabe9..0217c3f37 100644
--- a/src/problems/basic_problems.jl
+++ b/src/problems/basic_problems.jl
@@ -400,7 +400,7 @@ Documentation Page: https://docs.sciml.ai/Integrals/stable/
 
 ## Mathematical Specification of a data Integral Problem
 
-Data integral problems are defined as:
+Sampled integral problems are defined as:
 
 ```math
 \sum_i w_i y_i
@@ -413,7 +413,7 @@ assigned by a quadrature rule, which depend on sampling points `x`.
 ### Constructors
 
 ```
-DataIntegralProblem(x::AbstractVector, y::AbstractArray; dim=1, kwargs...)
+SampledIntegralProblem(x::AbstractVector, y::AbstractArray; dim=1, kwargs...)
 ```
 - y: The sampled integrand, must be a subtype of `AbstractArray`. 
   It is assumed that the values of `y` along dimension `dim` 
@@ -426,12 +426,12 @@ DataIntegralProblem(x::AbstractVector, y::AbstractArray; dim=1, kwargs...)
 
 The fields match the names of the constructor arguments.
 """
-struct DataIntegralProblem{Y, X, D, K} <: AbstractIntegralProblem{false}
+struct SampledIntegralProblem{Y, X, D, K} <: AbstractIntegralProblem{false}
     y::Y
     x::X
     dim::D
     kwargs::K
-    @add_kwonly function DataIntegralProblem(y::AbstractArray, x::AbstractVector;
+    @add_kwonly function SampledIntegralProblem(y::AbstractArray, x::AbstractVector;
         dim = 1,
         kwargs...)
         @assert dim <= ndims(y) "The integration dimension `dim` is larger than the number of dimensions of the integrand `y`"
@@ -441,7 +441,7 @@ struct DataIntegralProblem{Y, X, D, K} <: AbstractIntegralProblem{false}
     end
 end
 
-TruncatedStacktraces.@truncate_stacktrace DataIntegralProblem 1 4
+TruncatedStacktraces.@truncate_stacktrace SampledIntegralProblem 1 4
 
 @doc doc"""
 
diff --git a/test/function_building_error_messages.jl b/test/function_building_error_messages.jl
index 8fffc806b..c424a6f84 100644
--- a/test/function_building_error_messages.jl
+++ b/test/function_building_error_messages.jl
@@ -462,8 +462,8 @@ IntegralProblem(intf, [0.0], [1.0], p)
 
 x = [1.0, 2.0]
 y = rand(2, 2)
-DataIntegralProblem(y, x)
-DataIntegralProblem(y, x; dim=2)
+SampledIntegralProblem(y, x)
+SampledIntegralProblem(y, x; dim=2)
 
 # Optimization
 

From 1e960d185092f00a4fb460b0573f7e65d6cdcb31 Mon Sep 17 00:00:00 2001
From: IlianPihlajamaa <73794090+IlianPihlajamaa@users.noreply.github.com>
Date: Sun, 17 Sep 2023 11:28:26 +0200
Subject: [PATCH 15/15] change default dimension to `ndims(y)`

---
 src/problems/basic_problems.jl | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/problems/basic_problems.jl b/src/problems/basic_problems.jl
index 0217c3f37..e0385140d 100644
--- a/src/problems/basic_problems.jl
+++ b/src/problems/basic_problems.jl
@@ -413,13 +413,13 @@ assigned by a quadrature rule, which depend on sampling points `x`.
 ### Constructors
 
 ```
-SampledIntegralProblem(x::AbstractVector, y::AbstractArray; dim=1, kwargs...)
+SampledIntegralProblem(y::AbstractArray, x::AbstractVector; dim=ndims(y), kwargs...)
 ```
 - y: The sampled integrand, must be a subtype of `AbstractArray`. 
   It is assumed that the values of `y` along dimension `dim` 
   correspond to the integrand evaluated at sampling points `x`
 - x: Sampling points, must be a subtype of `AbstractVector`.   
-- dim: Dimension along which to integrate.
+- dim: Dimension along which to integrate. Defaults to the last dimension of `y`.
 - kwargs: Keyword arguments copied to the solvers.
 
 ### Fields
@@ -432,7 +432,7 @@ struct SampledIntegralProblem{Y, X, D, K} <: AbstractIntegralProblem{false}
     dim::D
     kwargs::K
     @add_kwonly function SampledIntegralProblem(y::AbstractArray, x::AbstractVector;
-        dim = 1,
+        dim = ndims(y),
         kwargs...)
         @assert dim <= ndims(y) "The integration dimension `dim` is larger than the number of dimensions of the integrand `y`"
         @assert length(x)==size(y, dim) "The integrand `y` must have the same length as the sampling points `x` along the integrated dimension."