Example usage for org.apache.commons.math.linear RealMatrixChangingVisitor visit

Introduction

In this page you can find the example usage for org.apache.commons.math.linear RealMatrixChangingVisitor visit.

Prototype

double visit(int row, int column, double value) throws MatrixVisitorException;

Source Link

Document

Visit one matrix entry.

Usage

From source file:org.mitre.math.linear.BufferRealMatrix.java

/** {@inheritDoc} */
@Override//from   www.  jav  a 2 s. c o  m
public double walkInOptimizedOrder(final RealMatrixChangingVisitor visitor) throws MatrixVisitorException {
    visitor.start(rows, columns, 0, rows - 1, 0, columns - 1);
    for (int iBlock = 0, blockIndex = 0; iBlock < blockRows; ++iBlock) {
        final int pStart = iBlock * BLOCK_SIZE;
        final int pEnd = Math.min(pStart + BLOCK_SIZE, rows);

        for (int jBlock = 0; jBlock < blockColumns; ++jBlock, ++blockIndex) {
            try {
                final int qStart = jBlock * BLOCK_SIZE;
                final int qEnd = Math.min(qStart + BLOCK_SIZE, columns);

                final long blockOffset = this.getBlockOffset(blockIndex);
                LOG.debug(String.format("BlockIndex=%d (offset=%d) pStart=%d pEnd=%d qStart=%d qEnd=%d",
                        blockIndex, blockOffset, pStart, pEnd, qStart, qEnd));

                final DoubleBuffer block = this.dataFileChannel
                        .map(FileChannel.MapMode.READ_WRITE, blockOffset, BLOCK_BYTE_SIZE).asDoubleBuffer();
                block.clear();

                for (int p = pStart, k = 0; p < pEnd; ++p) {
                    // jump to end of row incase we are not there
                    k = (p - pStart) * BLOCK_SIZE;
                    for (int q = qStart; q < qEnd; ++q, ++k) {
                        block.put(k, visitor.visit(p, q, block.get(k)));
                    }
                }
                this.dataFileChannel.force(false);
            } catch (IOException ioe) {
                throw new MathRuntimeException(
                        "IO Exception while visiting blockIndex {0} (iBlock={1}, jBlock={2})", blockIndex,
                        iBlock, jBlock);
            }
        }
    }
    return visitor.end();
}

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