<p>
Changes the sign of every element in the matrix.<br>
<br>
a<sub>ij</sub> = -a<sub>ij</sub>
</p>

@param a A matrix. Modified.
771755
public static void changeSign( DMatrix4x4 a )
    {
        a.a11 = -a.a11; a.a12 = -a.a12; a.a13 = -a.a13; a.a14 = -a.a14;
        a.a21 = -a.a21; a.a22 = -a.a22; a.a23 = -a.a23; a.a24 = -a.a24;
        a.a31 = -a.a31; a.a32 = -a.a32; a.a33 = -a.a33; a.a34 = -a.a34;
        a.a41 = -a.a41; a.a42 = -a.a42; a.a43 = -a.a43; a.a44 = -a.a44;
    }
147386
protected void commonSetup(DMatrixRMaj A) {
        setExpectedMaxSize(A.numRows,A.numCols);

        QR.set(A);
    }
1247897
public static void symmLowerToFull( DMatrixRMaj A )
    {
        if( A.numRows != A.numCols )
            throw new MatrixDimensionException("Must be a square matrix");

        final int cols = A.numCols;

        for (int row = 0; row < A.numRows; row++) {
            for (int col = row+1; col < cols; col++) {
                A.data[row*cols+col] = A.data[col*cols+row];
            }
        }
    }
1000736
public static void divide( DMatrix4 a , double alpha ) {
        a.a1 /= alpha;
        a.a2 /= alpha;
        a.a3 /= alpha;
        a.a4 /= alpha;
    }
891890
public static void setIdentity( DMatrix4x4 a ) {
        a.a11 = 1; a.a21 = 0; a.a31 = 0; a.a41 = 0;
        a.a12 = 0; a.a22 = 1; a.a32 = 0; a.a42 = 0;
        a.a13 = 0; a.a23 = 0; a.a33 = 1; a.a43 = 0;
        a.a14 = 0; a.a24 = 0; a.a34 = 0; a.a44 = 1;
    }
1220736
public static void fill( DMatrix4 a , double v  ) {
        a.a1 = v;
        a.a2 = v;
        a.a3 = v;
        a.a4 = v;
    }
448719
public static void changeSign( DMatrixD1 a )
    {
        final int size = a.getNumElements();

        for( int i = 0; i < size; i++ ) {
            a.data[i] = -a.data[i];
        }
    }
819024
public static void standard(DMatrix1Row A, DMatrix1Row A_tran)
    {
        int index = 0;
        for( int i = 0; i < A_tran.numRows; i++ ) {
            int index2 = i;

            int end = index + A_tran.numCols;
            while( index < end ) {
                A_tran.data[index++ ] = A.data[ index2 ];
                index2 += A.numCols;
            }
        }
    }
446686
public static void scale( double alpha , DMatrix2 a ) {
        a.a1 *= alpha;
        a.a2 *= alpha;
    }
16384
private static void resplit(final double a[]) {
        final double c = a[0] + a[1];
        final double d = -(c - a[0] - a[1]);

        if (c < 8e298 && c > -8e298) { // MAGIC NUMBER
            double z = c * HEX_40000000;
            a[0] = (c + z) - z;
            a[1] = c - a[0] + d;
        } else {
            double z = c * 9.31322574615478515625E-10;
            a[0] = (c + z - c) * HEX_40000000;
            a[1] = c - a[0] + d;
        }
    }
284075
public static void scale( double alpha , DMatrix4x4 a ) {
        a.a11 *= alpha; a.a12 *= alpha; a.a13 *= alpha; a.a14 *= alpha;
        a.a21 *= alpha; a.a22 *= alpha; a.a23 *= alpha; a.a24 *= alpha;
        a.a31 *= alpha; a.a32 *= alpha; a.a33 *= alpha; a.a34 *= alpha;
        a.a41 *= alpha; a.a42 *= alpha; a.a43 *= alpha; a.a44 *= alpha;
    }
89135
public void init( DMatrixRMaj A ) {
        if( A.numRows != A.numCols)
            throw new IllegalArgumentException("Must be square");

        if( A.numCols != N ) {
            N = A.numCols;
            QT.reshape(N,N, false);

            if( w.length < N ) {
                w = new double[ N ];
                gammas = new double[N];
                b = new double[N];
            }
        }

        // just copy the top right triangle
        QT.set(A);
    }
796806
public static void divRow(Matrix A, int i, double c)
    {
        divRow(A, i, 0, A.cols(), c);
    }
756592
protected void updateA( int w )
    {
        final double u[] = dataQR[w];

        for( int j = w+1; j < numCols; j++ ) {

            final double colQ[] = dataQR[j];
            // first element in u is assumed to be 1.0 + 0*i
            double realSum = colQ[w*2];
            double imagSum = colQ[w*2+1];

            for( int k = w+1; k < numRows; k++ ) {
                double realU = u[k*2];
                double imagU = -u[k*2+1];

                double realQ = colQ[k*2];
                double imagQ = colQ[k*2+1];

                realSum += realU*realQ - imagU*imagQ;
                imagSum += imagU*realQ + realU*imagQ;
            }
            realSum *= gamma;
            imagSum *= gamma;

            colQ[w*2  ] -= realSum;
            colQ[w*2+1] -= imagSum;

            for( int i = w+1; i < numRows; i++ ) {
                double realU = u[i*2];
                double imagU = u[i*2+1];

                colQ[i*2]  -= realU*realSum - imagU*imagSum;
                colQ[i*2+1]-= imagU*realSum + realU*imagSum;
            }
        }
    }
1130591
public static void divide( DMatrix2x2 a , double alpha ) {
        a.a11 /= alpha; a.a12 /= alpha;
        a.a21 /= alpha; a.a22 /= alpha;
    }
1236610
public static void fill( DMatrix3 a , double v  ) {
        a.a1 = v;
        a.a2 = v;
        a.a3 = v;
    }
940821
public static void add(DMatrixD1 a , double val ) {
        final int length = a.getNumElements();

        for( int i = 0; i < length; i++ ) {
            a.plus(i, val);
        }
    }