ccccrnr
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I am trying to write some code in JavaScript to use on my website that can take data in the from of a square matrix and invert the matrix to do Least Squares to generate an equation for the data.
I'm having a problem of reverse assignments.
Meaning the value i'm sending is getting changed by the operations I do later on the new varible in the function invertM
It is like a have done my varibles with pointers
but Javascript doesn't have Pointers or Constants(unfortuanately)
Please help me with the variables and this code. THANKS
I'm trying to test this with input like
the LinAlgerbraTool.js file looks like this
matrProd is to multply 2 matrix (testing this function works)
size is the dimention of the matrix [length, height] (this function works)
det is to calculate the determinant of the matrix sent to it (this function works)
invertM is to return the inverse matrix of the matrix sent to it ( Not work)
matscalmut is to multiply a scalar value into each cell in the sent matrix (this function works)
minormat is to help generate the matrix of minors for the inversion process for any size matrix (it is also to help seperate code and debug my invertM problem)
I'm having a problem of reverse assignments.
Meaning the value i'm sending is getting changed by the operations I do later on the new varible in the function invertM
It is like a have done my varibles with pointers
but Javascript doesn't have Pointers or Constants(unfortuanately)
Please help me with the variables and this code. THANKS
I'm trying to test this with input like
Code:
script src="LinAlgerbraTool.js" /script
script
var trym = new Array([1, 2, 3], [2, 3, 4], [3, 2, 1] );
var inv_try = invertM(trym);
document.write( inv_try );
/scriptthe LinAlgerbraTool.js file looks like this
Code:
function matxProd( a, b) {
var al = size(a);
var bl = size(b);
var mout = new Array();
if (al[0] != bl[1]) { alert("matrix deminsions can't be multiplyed" + al[0] + al[1]); return NaN; }
for(var j=0; j< bl[0]; j++) {
mout[j] = new Array();
for(var i=0; i< al[1]; i++) { // line 52 char 12 expect ';'
var c = 0;
for(var k=0; k< al[0] ; k++) {
c = a[k][i]*b[j][k] + c;
}
mout[j][i] = c;
}
}
return mout;
}
function size(a) { // size takes a vector or matrix => returns [length, height] h = 0 for vector
var b = new Array(2);
b[0] = a.length;
for(var i=0; a[0][i] != undefined ; i++) { }
b[1] = i;
return b;
}
function det(a) { // this is to take the determinant of the matrix a
var al = size(a);
if(al[0] != al[1]) {alert("matrix must be square"); return NaN; }
var d = 0;
var dp = 1;
var dd = 1;
for(var i=0; i<al[0]; i++) {
for(var j=0; j<al[0]; j++) {
if( (i+j) >= al[0] ) { dp = dp * a[i+j-al[0]][j]; dd = dd * a[2*al[0]-j-i-1][j];
}else { dp = dp * a[j+i][j]; dd = dd * a[al[0]-j-i-1][j]; }
}
d = d + dp - dd;
dp = 1;
dd = 1;
}
return d;
}
function invertM(ati) { // take the inverse of a matrix ati
var al = size(ati);
if(al[0] != al[1]) {alert("inverse matrix must be square"); return NaN; }
var detm = det(ati);
if(!detm) { alert("determinant of inverse Matrix can not = 0 "); return NaN; } // JS error line 105 by ie
var ain = new Array();
document.write("_ ati " + ati + "
");
for(var i=0; i<al[0] ; i++) {
ain[i] = new Array();
for(var j=0; j<al[0]; j++) {
var eventst = (i+j)/2; // test for even positive
if(Math.round(eventst) == eventst){ ain[i][j] = minormat(ati, i, j, al[0]) ; // build matrix of minors
}else{ ain[i][j] = -1 * minormat(ati, i, j, al[0]) ; }
}
}
ain = transp(ain);
ain = matscalmut( (1/detm), ain);
return ain;
}
function matscalmut( s, m) { // multiple the scalar value by each cell of matrix
var al = size(m);
for(var i=0; i<al[0] ; i++) {
for(var j=0; j<al[1]; j++) {
m[i][j] = s * m[i][j];
// if( (m[i][j]> -.0000001) && (m[i][j] < .0000001) ) { m[i][j] = 0; }
}
}
return m;
}
function minormat( amm, i, j, len) {
document.write(" in mat min " + amm); // line 123
for (var k=0; k<len; k++) {
amm[i][k] = 1;
amm[k][j] = 1;
}
document.write(" mat minor amm " + amm );
amm = det(amm);
document.write(" determinant amm " + amm + "
");
return amm;
}size is the dimention of the matrix [length, height] (this function works)
det is to calculate the determinant of the matrix sent to it (this function works)
invertM is to return the inverse matrix of the matrix sent to it ( Not work)
matscalmut is to multiply a scalar value into each cell in the sent matrix (this function works)
minormat is to help generate the matrix of minors for the inversion process for any size matrix (it is also to help seperate code and debug my invertM problem)