Java DoubleMatrix1D.viewPart方法代码示例

import cern.colt.matrix.DoubleMatrix1D; //导入方法依赖的package包/类
/**
 */
public static void doubleTest31(int size) {

System.out.println("\ninit");
DoubleMatrix1D a = Factory1D.dense.descending(size);
DoubleMatrix1D b = new WrapperDoubleMatrix1D(a);
DoubleMatrix1D c = b.viewPart(2,3);
DoubleMatrix1D d = c.viewFlip();
//DoubleMatrix1D c = b.viewFlip();
//DoubleMatrix1D d = c.viewFlip();
d.set(0,99);
b = b.viewSorted();
System.out.println("a = "+a);
System.out.println("b = "+b);
System.out.println("c = "+c);
System.out.println("d = "+d);

System.out.println("done");

}
 

import cern.colt.matrix.DoubleMatrix1D; //导入方法依赖的package包/类
/**
 */
public static void doubleTest6() {
int rows = 4;
int columns = 5; // make a 4*5 matrix
DoubleMatrix2D master = Factory2D.ascending(rows,columns);
//master.assign(1); // set all cells to 1
System.out.println("\n"+master);
master.viewPart(2,0,2,3).assign(2); // set [2,1] .. [3,3] to 2
System.out.println("\n"+master);

int[] indexes = {0,1,3,0,1,2};
DoubleMatrix1D view1 = master.viewRow(0).viewSelection(indexes);
System.out.println("view1="+view1);
DoubleMatrix1D view2 = view1.viewPart(0,3);
System.out.println("view2="+view2);

view2.viewPart(0,2).assign(-1);
System.out.println("master replaced"+master);
System.out.println("flip1 replaced"+view1);
System.out.println("flip2 replaced"+view2);


/*
DoubleMatrix2D copyPart = master.copyPart(2,1,2,3);
copyPart.assign(3); // modify an independent copy
copyPart.set(0,0,4);
System.out.println("\n"+copyPart); // has changed
System.out.println("\n"+master); // master has not changed

DoubleMatrix2D view1 = master.viewPart(0,3,4,2); // [0,3] .. [3,4]
DoubleMatrix2D view2 = view1.viewPart(0,0,4,1); // a view from a view 
System.out.println("\n"+view1);
System.out.println("\n"+view2);
*/
}
 

import cern.colt.matrix.DoubleMatrix1D; //导入方法依赖的package包/类
public void dgemv(final boolean transposeA, final double alpha, DoubleMatrix2D A, final DoubleMatrix1D x, final double beta, DoubleMatrix1D y) {
	/*
	split A, as follows:
	
			x x
			x
			x
	A
	xxx     x y
	xxx     x
	---     -
	xxx     x
	xxx     x
	---     -
	xxx     x

	*/
	if (transposeA) {
		dgemv(false, alpha, A.viewDice(), x, beta, y);
		return;
	}
	int m = A.rows();
	int n = A.columns();
	long flops = 2L*m*n;
	int noOfTasks = (int) Math.min(flops / 30000, this.maxThreads); // each thread should process at least 30000 flops
	int width = A.rows();
	noOfTasks = Math.min(width,noOfTasks);
	
	if (noOfTasks < 2) { // parallelization doesn't pay off (too much start up overhead)
		seqBlas.dgemv(transposeA, alpha, A, x, beta, y);
		return;
	}
	
	// set up concurrent tasks
	int span = width/noOfTasks;
	final FJTask[] subTasks = new FJTask[noOfTasks];
	for (int i=0; i<noOfTasks; i++) {
		final int offset = i*span;
		if (i==noOfTasks-1) span = width - span*i; // last span may be a bit larger

		// split A along rows into blocks
		final DoubleMatrix2D AA = A.viewPart(offset,0,span,n);
		final DoubleMatrix1D yy = y.viewPart(offset,span);
				
		subTasks[i] = new FJTask() { 
			public void run() { 
				seqBlas.dgemv(transposeA,alpha,AA,x,beta,yy); 
				//System.out.println("Hello "+offset); 
			}
		};
	}
	
	// run tasks and wait for completion
	try { 
		this.smp.taskGroup.invoke(
			new FJTask() {
				public void run() {	
					coInvoke(subTasks);	
				}
			}
		);
	} catch (InterruptedException exc) {}
}