det.hhs

/**
 * @author Jason Reynolds
 * @param input the square matrix to take in and find the determinant of
 * @returns the determinant of the matrix, as a number
 * 
 * functions finds determinant of a matrix, wrapper functions from mathjs
 */



function det(input) {

    *import math: ndim

    // wrong argument number
    if (arguments.length === 0) {
        throw new Error('Exception occurred in det - no argument given');
    }
    else if (arguments.length > 1) {
        throw new Error('Exception occurred in det - wrong argument number');
    }

    // type check
    if (!(Array.isArray(input)) && !(input instanceof Mat) && !(input instanceof Tensor)) {
        throw new Error('Exception occurred in det - input is not a Mat, Tensor or JS Array');
    }

    // dimension check
    if (ndim(input) !== 2) {
        throw new Error('Exception occurred in det - input is not 2-dimensional');
    }

    //set raw_in to be either a clone of Mat or input itself if JS array
    let in_type = (input instanceof Mat) || (input instanceof Tensor);
    let raw_in = (in_type) ? input.clone() : input;

    //in the case that it's an input of Mat
    if (input instanceof Mat) {

        //check the dimensions: are rows, cols 0? is it not square? if so, throw error 
        if (input.rows === 0 || input.cols === 0 || !(input.rows === input.cols)) {
            throw new Error('Exception occurred in det - wrong dimensions for input');
        }
        //since it's Mat, degrade to JS array
        raw_in = raw_in.val;
        //plug it into mathjs.det and return 
        return mathjs.det(raw_in);

    }

    //in the case that it's a JS array or Tensor
    else {
        //again check the input. is any dim 0? is it not square? if so, throw error.
        if (in_type) {
            input = raw_in.val;
        }
        if (input.length === 0 || input[0].length === 0 || !(input.length === input[0].length)) {
            throw new Error('Exception occurred in det - wrong dimensions for input');
        }
        //plug in input clone into mathjs.det and return. Technically since det doesn't modify you could use parameter 'input'
        return mathjs.det(input);
    }
}