package symjava.examples;

import static symjava.symbolic.Symbol.x;
import static symjava.math.SymMath.*;

import java.util.ArrayList;

import symjava.bytecode.BytecodeVecFunc;
import symjava.bytecode.BytecodeFunc;
import symjava.symbolic.Expr;
import symjava.symbolic.Func;
import symjava.symbolic.utils.JIT;

public class BenchmarkTaylor {
	public static double factorial(int n) {
		double rlt = 1;
		for(int i=1; i<=n; i++)
			rlt *= i;
		return rlt;
	}
	public static void main(String[] args) {
		//test();
		testBatchEval();
	}
	
	public static void test() {
		int n = 10;
		Expr expr = 0;
		
		Expr term;
		ArrayList<Expr> exprs = new ArrayList<Expr>();
		for(int i=0; i<n; i++) {
			term = (1.0/factorial(i))*pow(x, i);
			//System.out.println(term);
			expr = expr + term;
			exprs.add(expr);
		}
		
		ArrayList<BytecodeFunc> funcs = new ArrayList<BytecodeFunc>();
		for(int i=0; i<n; i++) {
			Func func = new Func("func"+i, exprs.get(i));
			BytecodeFunc bfunc = func.toBytecodeFunc();
			System.out.println(bfunc.apply(0.1));
			funcs.add(bfunc);
		}
		
		int N=10000000;
		double xx = 0.1;
		double out = 0.0;
		for(int i=0; i<funcs.size(); i++) {
			long begin = System.currentTimeMillis();
			for(int j=0; j<N; j++) {
				xx += 1e-15;
				out += funcs.get(i).apply(xx);
			}
			long end = System.currentTimeMillis();
			System.out.println("Time: "+((end-begin)/1000.0)+" expr="+exprs.get(i));
		}
		System.out.println("Test Value="+out);
	}
	
	public static void testBatchEval() {
		int n = 10;
		Expr expr = 0;
		
		Expr term;
		ArrayList<Expr> exprs = new ArrayList<Expr>();
		for(int i=0; i<n; i++) {
			term = (1.0/factorial(i))*pow(x, i);
			//System.out.println(term);
			expr = expr + term;
			exprs.add(expr);
		}
		
		ArrayList<BytecodeVecFunc> funcs = new ArrayList<BytecodeVecFunc>();
		int batchLen = 100000;
		double[] outAry = new double[batchLen];
		double[] args = new double[batchLen];
		
		for(int i=0; i<n; i++) {
			Func func = new Func("func"+i, exprs.get(i));
			BytecodeVecFunc bfunc = JIT.compileVecFunc(func.args(), func);
			funcs.add(bfunc);
		}
		
		int N=10000000/batchLen;
		double out = 0.0;
		double xx = 0.1;
		for(int i=0; i<funcs.size(); i++) {
			long begin = System.currentTimeMillis();
			for(int j=0; j<N; j++) {
				for(int k=0; k<batchLen; k++) {
					xx += 1e-15;
					args[k] = xx;
				}
				funcs.get(i).apply(outAry, 0, args);
				for(int k=0; k<batchLen; k++)
					out += outAry[k];
			}
			long end = System.currentTimeMillis();
			System.out.println("Time: "+((end-begin)/1000.0)+" expr="+exprs.get(i));
		}
		System.out.println("Test Value="+out);
	}

}