finishing touches, renam to fft_vartime

mratsim · Sep 3, 2023 · e4c0989 · e4c0989
1 parent 4661e82
commit e4c0989
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Showing 3 changed files with 22 additions and 21 deletions.
diff --git a/constantine/math/elliptic/ec_scalar_mul_vartime.nim b/constantine/math/elliptic/ec_scalar_mul_vartime.nim
@@ -360,7 +360,7 @@ func scalarMul_vartime*[scalBits; EC](
 
   let usedBits = scalar.limbs.getBits_vartime()
 
-  when scalBits == EC.F.C.getCurveOrderBitwidth and
+  when scalBits == EC.F.C.getCurveOrderBitwidth() and
        EC.F.C.hasEndomorphismAcceleration():
     if usedBits >= L:
       when EC.F is Fp:

diff --git a/constantine/math/polynomials/fft.nim b/constantine/math/polynomials/fft.nim
@@ -104,7 +104,7 @@ func fft_internal[EC; bits: static int](
     output[i+half] .diff_vartime(output[i], y_times_root)
     output[i]      .sum_vartime(output[i], y_times_root)
 
-func fft*[EC](
+func fft_vartime*[EC](
        desc: ECFFT_Descriptor[EC],
        output: var openarray[EC],
        vals: openarray[EC]): FFT_Status =
@@ -121,7 +121,7 @@ func fft*[EC](
   fft_internal(voutput, vals.toStridedView(), rootz)
   return FFTS_Success
 
-func ifft*[EC](
+func ifft_vartime*[EC](
        desc: ECFFT_Descriptor[EC],
        output: var openarray[EC],
        vals: openarray[EC]): FFT_Status =
@@ -360,12 +360,12 @@ when isMainModule:
       data[i].madd(data[i-1], BLS12_381.getGenerator("G1"))
 
     var coefs = newSeq[EC_G1](data.len)
-    let fftOk = fft(fftDesc, coefs, data)
+    let fftOk = fft_vartime(fftDesc, coefs, data)
     doAssert fftOk == FFTS_Success
     # display("coefs", 0, coefs)
 
     var res = newSeq[EC_G1](data.len)
-    let ifftOk = ifft(fftDesc, res, coefs)
+    let ifftOk = ifft_vartime(fftDesc, res, coefs)
     doAssert ifftOk == FFTS_Success
     # display("res", 0, res)
 
@@ -415,7 +415,7 @@ when isMainModule:
       # Bench
       let start = getMonotime()
       for i in 0 ..< NumIters:
-        let status = fftDesc.fft(coefsOut, data)
+        let status = fftDesc.fft_vartime(coefsOut, data)
         doAssert status == FFTS_Success
       let stop = getMonotime()
 

diff --git a/research/kzg/fft_g1.nim b/research/kzg/fft_g1.nim
@@ -96,28 +96,29 @@ func expandRootOfUnity[F](rootOfUnity: F): auto {.noInit.} =
 func simpleFT[EC; bits: static int](
        output: var View[EC],
        vals: View[EC],
-       rootsOfUnity: View[BigInt[bits]]
-     ) =
+       rootsOfUnity: View[BigInt[bits]]) =
   # FFT is a recursive algorithm
   # This is the base-case using a O(n²) algorithm
 
   let L = output.len
   var last {.noInit.}, v {.noInit.}: EC
 
+  var v0w0 {.noInit.} = vals[0]
+  v0w0.scalarMul_vartime(rootsOfUnity[0])
+
   for i in 0 ..< L:
-    last = vals[0]
-    last.scalarMul_vartime(rootsOfUnity[0])
+    last = v0w0
     for j in 1 ..< L:
       v = vals[j]
+
       v.scalarMul_vartime(rootsOfUnity[(i*j) mod L])
-      last += v
+      last.sum_vartime(last, v)
     output[i] = last
 
 func fft_internal[EC; bits: static int](
        output: var View[EC],
        vals: View[EC],
-       rootsOfUnity: View[BigInt[bits]]
-     ) =
+       rootsOfUnity: View[BigInt[bits]]) =
   if output.len <= 4:
     simpleFT(output, vals, rootsOfUnity)
     return
@@ -137,10 +138,10 @@ func fft_internal[EC; bits: static int](
     # FFT Butterfly
     y_times_root = output[i+half]
     y_times_root   .scalarMul_vartime(rootsOfUnity[i])
-    output[i+half] .diff(output[i], y_times_root)
-    output[i]      += y_times_root
+    output[i+half] .diff_vartime(output[i], y_times_root)
+    output[i]      .sum_vartime(output[i], y_times_root)
 
-func fft*[EC](
+func fft_vartime*[EC](
        desc: FFTDescriptor[EC],
        output: var openarray[EC],
        vals: openarray[EC]): FFT_Status =
@@ -157,7 +158,7 @@ func fft*[EC](
   fft_internal(voutput, vals.toView(), rootz)
   return FFTS_Success
 
-func ifft*[EC](
+func ifft_vartime*[EC](
        desc: FFTDescriptor[EC],
        output: var openarray[EC],
        vals: openarray[EC]): FFT_Status =
@@ -180,7 +181,7 @@ func ifft*[EC](
   invLen.inv_vartime()
   let inv = invLen.toBig()
 
-  for i in 0..< output.len:
+  for i in 0 ..< output.len:
     output[i].scalarMul_vartime(inv)
 
   return FFTS_Success
@@ -222,12 +223,12 @@ when isMainModule:
       data[i].madd(data[i-1], Generator1)
 
     var coefs = newSeq[EC_G1](data.len)
-    let fftOk = fft(fftDesc, coefs, data)
+    let fftOk = fft_vartime(fftDesc, coefs, data)
     doAssert fftOk == FFTS_Success
     # display("coefs", 0, coefs)
 
     var res = newSeq[EC_G1](data.len)
-    let ifftOk = ifft(fftDesc, res, coefs)
+    let ifftOk = ifft_vartime(fftDesc, res, coefs)
     doAssert ifftOk == FFTS_Success
     # display("res", 0, res)
 
@@ -277,7 +278,7 @@ when isMainModule:
       # Bench
       let start = getMonotime()
       for i in 0 ..< NumIters:
-        let status = desc.fft(coefsOut, data)
+        let status = desc.fft_vartime(coefsOut, data)
         doAssert status == FFTS_Success
       let stop = getMonotime()