From 2ede6db86243e59223cd89e6debd7107d02eabd5 Mon Sep 17 00:00:00 2001
From: Jaron Kent-Dobias <jaron@kent-dobias.com>
Date: Sun, 20 Apr 2025 12:44:38 -0300
Subject: Standardized saving and loading of files

---
 log-fourier.cpp | 89 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 89 insertions(+)

(limited to 'log-fourier.cpp')

diff --git a/log-fourier.cpp b/log-fourier.cpp
index 7461a70..f7d6f4b 100644
--- a/log-fourier.cpp
+++ b/log-fourier.cpp
@@ -1,5 +1,7 @@
 #include "log-fourier.hpp"
+#include "p-spin.hpp"
 #include <complex>
+#include <fstream>
 
 LogarithmicFourierTransform::LogarithmicFourierTransform(unsigned N, Real k, Real Δτ, unsigned pad) : N(N), pad(pad), k(k), Δτ(Δτ) {
   τₛ = -0.5 * N;
@@ -106,3 +108,90 @@ std::vector<Real> LogarithmicFourierTransform::inverse(const std::vector<Complex
   return c;
 }
 
+std::string logFourierFile(std::string prefix, unsigned p, unsigned s, Real λ, Real τ₀, Real β, unsigned log2n, Real Δτ, Real k) {
+  return prefix + "_" + std::to_string(p) + "_" + std::to_string(s) + "_" + std::to_string(λ) + "_" + std::to_string(τ₀) + "_" + std::to_string(β) + "_" + std::to_string(log2n) + "_" + std::to_string(Δτ)  + "_" + std::to_string(k) + ".dat";
+}
+
+void logFourierSave(const std::vector<Real>& C, const std::vector<Real>& R, const std::vector<Complex>& Ct, const std::vector<Complex>& Rt, unsigned p, unsigned s, Real λ, Real τ₀, Real β, unsigned log2n, Real Δτ, Real k) {
+    unsigned N = pow(2, log2n);
+    std::ofstream outfile(logFourierFile("C", p, s, λ, τ₀, β, log2n, Δτ, k), std::ios::out | std::ios::binary);
+    outfile.write((const char*)(C.data()), N * sizeof(Real));
+    outfile.close();
+
+    std::ofstream outfileCt(logFourierFile("Ct", p, s, λ, τ₀, β, log2n, Δτ, k), std::ios::out | std::ios::binary);
+    outfileCt.write((const char*)(Ct.data()), N * sizeof(Complex));
+    outfileCt.close();
+
+    std::ofstream outfileR(logFourierFile("R", p, s, λ, τ₀, β, log2n, Δτ, k), std::ios::out | std::ios::binary);
+    outfileR.write((const char*)(R.data()), N * sizeof(Real));
+    outfileR.close();
+
+    std::ofstream outfileRt(logFourierFile("Rt", p, s, λ, τ₀, β, log2n, Δτ, k), std::ios::out | std::ios::binary);
+    outfileRt.write((const char*)(Rt.data()), N * sizeof(Complex));
+    outfileRt.close();
+}
+
+bool logFourierLoad(std::vector<Real>& C, std::vector<Real>& R, std::vector<Complex>& Ct, std::vector<Complex>& Rt, unsigned p, unsigned s, Real λ, Real τ₀, Real β, unsigned log2n, Real Δτ, Real k) {
+  std::ifstream cfile(logFourierFile("C", p, s, λ, τ₀, β, log2n, Δτ, k), std::ios::binary);
+  std::ifstream rfile(logFourierFile("R", p, s, λ, τ₀, β, log2n, Δτ, k), std::ios::binary);
+  std::ifstream ctfile(logFourierFile("Ct", p, s, λ, τ₀, β, log2n, Δτ, k), std::ios::binary);
+  std::ifstream rtfile(logFourierFile("Rt", p, s, λ, τ₀, β, log2n, Δτ, k), std::ios::binary);
+
+  if ((!cfile.is_open() || !rfile.is_open()) || (!ctfile.is_open() || !rtfile.is_open())) {
+    return false;
+  }
+
+  unsigned N = pow(2, log2n);
+
+  cfile.read((char*)(C.data()), N * sizeof(Real));
+  cfile.close();
+
+  rfile.read((char*)(R.data()), N * sizeof(Real));
+  rfile.close();
+
+  ctfile.read((char*)(Ct.data()), N * sizeof(Complex));
+  ctfile.close();
+
+  rtfile.read((char*)(Rt.data()), N * sizeof(Complex));
+  rtfile.close();
+
+  return true;
+}
+
+std::tuple<std::vector<Complex>, std::vector<Complex>> RddfCtdfCt(LogarithmicFourierTransform& fft, const std::vector<Real>& C, const std::vector<Real>& R, unsigned p, unsigned s, Real λ) {
+  std::vector<Real> dfC(C.size());
+  std::vector<Real> RddfC(C.size());
+  for (unsigned n = 0; n < C.size(); n++) {
+    RddfC[n] = R[n] * ddf(λ, p, s, C[n]);
+    dfC[n] = df(λ, p, s, C[n]);
+  }
+  std::vector<Complex> RddfCt = fft.fourier(RddfC, false);
+  std::vector<Complex> dfCt = fft.fourier(dfC, true);
+
+  return {RddfCt, dfCt};
+}
+
+Real estimateZ(LogarithmicFourierTransform& fft, const std::vector<Real>& C, const std::vector<Complex>& Ct, const std::vector<Real>& R, const std::vector<Complex>& Rt, unsigned p, unsigned s, Real λ, Real τ₀, Real β) {
+  auto [RddfCt, dfCt] = RddfCtdfCt(fft, C, R, p, s, λ);
+  Real Γ₀ = 1 + τ₀;
+
+  return ((2 * Γ₀ * std::conj(Rt[0]) + pow(β, 2) * (RddfCt[0] * Ct[0] + dfCt[0] * std::conj(Rt[0]))) / Ct[0]).real();
+}
+
+Real energy(const LogarithmicFourierTransform& fft, std::vector<Real>&  C, const std::vector<Real>& R, unsigned p, unsigned s, Real λ, Real β) {
+  Real E = 0;
+  for (unsigned n = 0; n < C.size()/2-1; n++) {
+    Real h₂ₙ   = fft.t(2*n+1) - fft.t(2*n);
+    Real h₂ₙ₊₁ = fft.t(2*n+2) - fft.t(2*n+1);
+    Real f₂ₙ   = R[2*n]   * df(λ, p, s, C[2*n]);
+    Real f₂ₙ₊₁ = R[2*n+1] * df(λ, p, s, C[2*n+1]);
+    Real f₂ₙ₊₂ = R[2*n+2] * df(λ, p, s, C[2*n+2]);
+    E += (h₂ₙ + h₂ₙ₊₁) / 6 * (
+          (2 - h₂ₙ₊₁ / h₂ₙ) * f₂ₙ
+          + pow(h₂ₙ + h₂ₙ₊₁, 2) / (h₂ₙ * h₂ₙ₊₁) * f₂ₙ₊₁
+          + (2 - h₂ₙ / h₂ₙ₊₁) * f₂ₙ₊₂
+        );
+  }
+  return  β * E;
+}
+
-- 
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