AmiBroker 6.00 has introduced support for matrices. After we create a matrics with Matrix function call:
my_var_name = Matrix( rows, cols, initvalue);
then in order to access matrix elements, we need to use:
x = my_var_name[ row ][ col ];
However – if we want to populate a relatively large matrix with values generated in other programs, then it may not be very practical to do it by hand in the AFL code assigning individual elements like this:
A[ 0 ][ 0 ] = 1; A[ 0 ][ 1 ] = 4; A[ 0 ][ 2 ] = 6;
What we can do in such case is to store the values in a text file that we could use as input, then read through the file using fgets function and populate Matrix elements using a looping code. A sample formula showing how to perform such task is presented below.
A sample text file for this example can be found here: http://www.amibroker.com/kb/wp-content/uploads/2015/10/samplematrix.txt
// the input file path file = "C:\\samplematrix.txt"; // define the size of the desired matrix rows = 16; cols = 16; // create matrix myMatrix = Matrix( rows, cols, 0 ); // open file fh = fopen( file, "r" ); if( fh ) { i = 0; // iterate through the lines of input file for( i = 0; ! feof( fh ) AND i < rows; i++ ) { // read a line of text line = fgets( fh ); if( line == "" ) { Error("Too few rows in the data file or an empty row found"); break; } // iterate through the elements of the line for( j = 0; ( item = StrExtract( line, j ) ) != "" AND j < cols; j++ ) { // assign matrix element myMatrix[ i ][ j ] = StrToNum( item ); } if( j < cols ) { Error("Too few columns in data file"); break; } } fclose( fh ); } else { Error( "ERROR: file can not be opened" ); } // spot check selected element Title = "spot check M[ 2 ][ 3 ]: " + NumToStr( MyMatrix[ 2 ][ 3 ] );