comparison fft/fft.js/src/complex.erb.js @ 25:66f9fd5ac611

Bring in some more of the third-party code

+<%= $:.unshift('.'); require "#{File.dirname(__FILE__)}/../src/complex.rb"; File.read "#{File.dirname(__FILE__)}/../LICENSE" %>
+
+if (!FFT) {
+	var FFT = {}
+}
+
+void function (namespace) {
+	"use strict"
+	
+	function butterfly2(output, outputOffset, outputStride, fStride, state, m) {
+		var t = state.twiddle
+		
+		for (var i = 0; i < m; i++) {
+			<%= load('s0', 'output', 'outputOffset', 'i', 'outputStride') %>
+			<%= load('s1', 'output', 'outputOffset', 'i + m', 'outputStride') %>
+			
+			<%= load('t1', 't', 0, 'i', 'fStride') %>
+			
+			<%= cmul('v1', 's1', 't1') %>
+			
+			<%= cadd('r0', 's0', 'v1') %>
+			<%= csub('r1', 's0', 'v1') %>
+			
+			<%= store('r0', 'output', 'outputOffset', 'i', 'outputStride') %>
+			<%= store('r1', 'output', 'outputOffset', 'i + m', 'outputStride') %>
+		}
+	}
+	
+	function butterfly3(output, outputOffset, outputStride, fStride, state, m) {
+		var t = state.twiddle
+		var m1 = m, m2 = 2 * m
+		var fStride1 = fStride, fStride2 = 2 * fStride
+		
+		var e = <%= imag('t', 0, 'm', 'fStride') %>
+		
+		for (var i = 0; i < m; i++) {
+			<%= load('s0', 'output', 'outputOffset', 'i', 'outputStride') %>
+			
+			<%= load('s1', 'output', 'outputOffset', 'i + m1', 'outputStride') %>
+			<%= load('t1', 't', 0, 'i', 'fStride1') %>
+			<%= cmul('v1', 's1', 't1') %>
+			
+			<%= load('s2', 'output', 'outputOffset', 'i + m2', 'outputStride') %>
+			<%= load('t2', 't', 0, 'i', 'fStride2') %>
+			<%= cmul('v2', 's2', 't2') %>
+			
+			<%= cadd('i0', 'v1', 'v2') %>
+			
+			<%= cadd('r0', 's0', 'i0') %>
+			<%= store('r0', 'output', 'outputOffset', 'i', 'outputStride') %>
+			
+			var i1_r = s0_r - i0_r * 0.5
+			var i1_i = s0_i - i0_i * 0.5
+			
+			var i2_r = (v1_r - v2_r) * e
+			var i2_i = (v1_i - v2_i) * e
+			
+			var r1_r = i1_r - i2_i
+			var r1_i = i1_i + i2_r
+			<%= store('r1', 'output', 'outputOffset', 'i + m1', 'outputStride') %>
+			
+			var r2_r = i1_r + i2_i
+			var r2_i = i1_i - i2_r
+			<%= store('r2', 'output', 'outputOffset', 'i + m2', 'outputStride') %>
+		}
+	}
+	
+	function butterfly4(output, outputOffset, outputStride, fStride, state, m) {
+		var t = state.twiddle
+		var m1 = m, m2 = 2 * m, m3 = 3 * m
+		var fStride1 = fStride, fStride2 = 2 * fStride, fStride3 = 3 * fStride
+		
+		for (var i = 0; i < m; i++) {
+			<%= load('s0', 'output', 'outputOffset', 'i', 'outputStride') %>
+			
+			<%= load('s1', 'output', 'outputOffset', 'i + m1', 'outputStride') %>
+			<%= load('t1', 't', 0, 'i', 'fStride1') %>
+			<%= cmul('v1', 's1', 't1') %>
+			
+			<%= load('s2', 'output', 'outputOffset', 'i + m2', 'outputStride') %>
+			<%= load('t2', 't', 0, 'i', 'fStride2') %>
+			<%= cmul('v2', 's2', 't2') %>
+			
+			<%= load('s3', 'output', 'outputOffset', 'i + m3', 'outputStride') %>
+			<%= load('t3', 't', 0, 'i', 'fStride3') %>
+			<%= cmul('v3', 's3', 't3') %>
+			
+			<%= cadd('i0', 's0', 'v2') %>
+			<%= csub('i1', 's0', 'v2') %>
+			<%= cadd('i2', 'v1', 'v3') %>
+			<%= csub('i3', 'v1', 'v3') %>
+			
+			<%= cadd('r0', 'i0', 'i2') %>
+			
+			if (state.inverse) {
+				var r1_r = i1_r - i3_i
+				var r1_i = i1_i + i3_r
+			} else {
+				var r1_r = i1_r + i3_i
+				var r1_i = i1_i - i3_r
+			}
+			
+			<%= csub('r2', 'i0', 'i2') %>
+			
+			if (state.inverse) {
+				var r3_r = i1_r + i3_i
+				var r3_i = i1_i - i3_r
+			} else {
+				var r3_r = i1_r - i3_i
+				var r3_i = i1_i + i3_r
+			}
+			
+			<%= store('r0', 'output', 'outputOffset', 'i', 'outputStride') %>
+			<%= store('r1', 'output', 'outputOffset', 'i + m1', 'outputStride') %>
+			<%= store('r2', 'output', 'outputOffset', 'i + m2', 'outputStride') %>
+			<%= store('r3', 'output', 'outputOffset', 'i + m3', 'outputStride') %>
+		}
+	}
+	
+	function butterfly(output, outputOffset, outputStride, fStride, state, m, p) {
+		var t = state.twiddle, n = state.n, scratch = new Float64Array(2 * p)
+		
+		for (var u = 0; u < m; u++) {
+			for (var q1 = 0, k = u; q1 < p; q1++, k += m) {
+				<%= load('x0', 'output', 'outputOffset', 'k', 'outputStride') %>
+				<%= store('x0', 'scratch', 'q1') %>
+			}
+			
+			for (var q1 = 0, k = u; q1 < p; q1++, k += m) {
+				var tOffset = 0
+				
+				<%= load('x0', 'scratch', 0) %>
+				<%= store('x0', 'output', 'outputOffset', 'k', 'outputStride') %>
+				
+				for (var q = 1; q < p; q++) {
+					tOffset = (tOffset + fStride * k) % n
+					
+					<%= load('s0', 'output', 'outputOffset', 'k', 'outputStride') %>
+					
+					<%= load('s1', 'scratch', 'q') %>
+					<%= load('t1', 't', 'tOffset') %>
+					<%= cmul('v1', 's1', 't1') %>
+					
+					<%= cadd('r0', 's0', 'v1') %>
+					<%= store('r0', 'output', 'outputOffset', 'k', 'outputStride') %>
+				}
+			}
+		}
+	}
+	
+	function work(output, outputOffset, outputStride, f, fOffset, fStride, inputStride, factors, state) {
+		var p = factors.shift()
+		var m = factors.shift()
+		
+		if (m == 1) {
+			for (var i = 0; i < p * m; i++) {
+				<%= load('x0', 'f', 'fOffset', 'i', 'fStride * inputStride') %>
+				<%= store('x0', 'output', 'outputOffset', 'i', 'outputStride') %>
+			}
+		} else {
+			for (var i = 0; i < p; i++) {
+				work(output, outputOffset + outputStride * i * m, outputStride, f, fOffset + i * fStride * inputStride, fStride * p, inputStride, factors.slice(), state)
+			}
+		}
+		
+		switch (p) {
+			case 2: butterfly2(output, outputOffset, outputStride, fStride, state, m); break
+			case 3: butterfly3(output, outputOffset, outputStride, fStride, state, m); break
+			case 4: butterfly4(output, outputOffset, outputStride, fStride, state, m); break
+			default: butterfly(output, outputOffset, outputStride, fStride, state, m, p); break
+		}
+	}
+	
+	var complex = function (n, inverse) {
+		if (arguments.length < 2) {
+			throw new RangeError("You didn't pass enough arguments, passed `" + arguments.length + "'")
+		}
+		
+		var n = ~~n, inverse = !!inverse
+		
+		if (n < 1) {
+			throw new RangeError("n is outside range, should be positive integer, was `" + n + "'")
+		}
+		
+		var state = {
+			n: n,
+			inverse: inverse,
+			
+			factors: [],
+			twiddle: new Float64Array(2 * n),
+			scratch: new Float64Array(2 * n)
+		}
+		
+		var t = state.twiddle, theta = 2 * Math.PI / n
+		
+		for (var i = 0; i < n; i++) {
+			if (inverse) {
+				var phase =  theta * i
+			} else {
+				var phase = -theta * i
+			}
+			
+			<%= real('t', 'i') %> = Math.cos(phase)
+			<%= imag('t', 'i') %> = Math.sin(phase)
+		}
+		
+		var p = 4, v = Math.floor(Math.sqrt(n))
+		
+		while (n > 1) {
+			while (n % p) {
+				switch (p) {
+					case 4: p = 2; break
+					case 2: p = 3; break
+					default: p += 2; break
+				}
+				
+				if (p > v) {
+					p = n
+				}
+			}
+			
+			n /= p
+			
+			state.factors.push(p)
+			state.factors.push(n)
+		}
+		
+		this.state = state
+	}
+	
+	complex.prototype.simple = function (output, input, t) {
+		this.process(output, 0, 1, input, 0, 1, t)
+	}
+	
+	complex.prototype.process = function(output, outputOffset, outputStride, input, inputOffset, inputStride, t) {
+		var outputStride = ~~outputStride, inputStride = ~~inputStride
+		
+		var type = t == 'real' ? t : 'complex'
+		
+		if (outputStride < 1) {
+			throw new RangeError("outputStride is outside range, should be positive integer, was `" + outputStride + "'")
+		}
+		
+		if (inputStride < 1) {
+			throw new RangeError("inputStride is outside range, should be positive integer, was `" + inputStride + "'")
+		}
+		
+		if (type == 'real') {
+			for (var i = 0; i < this.state.n; i++) {
+				var x0_r = input[inputOffset + inputStride * i]
+				var x0_i = 0.0
+				
+				<%= store('x0', 'this.state.scratch', 'i') %>
+			}
+			
+			work(output, outputOffset, outputStride, this.state.scratch, 0, 1, 1, this.state.factors.slice(), this.state)
+		} else {
+			if (input == output) {
+				work(this.state.scratch, 0, 1, input, inputOffset, 1, inputStride, this.state.factors.slice(), this.state)
+				
+				for (var i = 0; i < this.state.n; i++) {
+					<%= load('x0', 'this.state.scratch', 'i') %>
+					
+					<%= store('x0', 'output', 'outputOffset', 'i', 'outputStride') %>
+				}
+			} else {
+				work(output, outputOffset, outputStride, input, inputOffset, 1, inputStride, this.state.factors.slice(), this.state)
+			}
+		}
+	}
+	
+	namespace.complex = complex
+}(FFT)