io.warp10.script.functions.TOMAT.java Source code

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Here is the source code for io.warp10.script.functions.TOMAT.java

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//
//   Copyright 2016  Cityzen Data
//
//   Licensed under the Apache License, Version 2.0 (the "License");
//   you may not use this file except in compliance with the License.
//   You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
//   Unless required by applicable law or agreed to in writing, software
//   distributed under the License is distributed on an "AS IS" BASIS,
//   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//   See the License for the specific language governing permissions and
//   limitations under the License.
//

package io.warp10.script.functions;

import java.util.List;

import org.apache.commons.math3.linear.MatrixUtils;
import org.apache.commons.math3.linear.RealMatrix;
import org.apache.commons.math3.linear.RealVector;

import io.warp10.script.NamedWarpScriptFunction;
import io.warp10.script.WarpScriptStackFunction;
import io.warp10.script.WarpScriptException;
import io.warp10.script.WarpScriptStack;

/**
 * Converts nested lists of numbers into a Matrix
 */
public class TOMAT extends NamedWarpScriptFunction implements WarpScriptStackFunction {

    public TOMAT(String name) {
        super(name);
    }

    @Override
    public Object apply(WarpScriptStack stack) throws WarpScriptException {

        Object o = stack.pop();

        if (o instanceof RealVector) {

            RealMatrix matrix = MatrixUtils.createRealMatrix(((RealVector) o).getDimension(), 1);

            matrix.setColumnVector(0, (RealVector) o);

            stack.push(matrix);

            return stack;
        }

        if (!(o instanceof List)) {
            throw new WarpScriptException(getName() + " expects a 2D array onto the stack.");
        }

        int rows = ((List) o).size();
        int cols = -1;

        for (Object oo : (List) o) {
            if (!(oo instanceof List)) {
                throw new WarpScriptException(getName() + " expects a 2D array onto the stack.");
            }
            if (-1 == cols) {
                cols = ((List) oo).size();
            } else if (cols != ((List) oo).size()) {
                throw new WarpScriptException(
                        getName() + " expects a common number of columns throughout the 2D array.");
            }
        }

        double[][] doubles = new double[rows][cols];

        for (int i = 0; i < rows; i++) {
            List<Object> row = (List<Object>) ((List) o).get(i);
            for (int j = 0; j < cols; j++) {
                Object elt = row.get(j);
                if (!(elt instanceof Number)) {
                    throw new WarpScriptException(getName() + " expects a numeric 2D array onto the stack.");
                }
                doubles[i][j] = ((Number) elt).doubleValue();
            }
        }

        RealMatrix mat = MatrixUtils.createRealMatrix(doubles);

        stack.push(mat);

        return stack;
    }
}