Blog Entry (c) Wednesday, August 13, 2025, by James Pate Williams, Jr. Exercises from an Online Textbook

#include <complex>
#include <vector>

class CmpLinearAlgebra
{
public:
    static void CmpPrintMatrix(
        int m, int n,
        std::vector<std::vector<std::complex<double>>>& Ac);
    static void CmpAddition(
        size_t m, size_t n,
        std::vector<std::vector<std::complex<double>>>& A,
        std::vector<std::vector<std::complex<double>>>& B,
        std::vector<std::vector<std::complex<double>>>& C);
    static void CmpSubtraction(
        size_t m, size_t n,
        std::vector<std::vector<std::complex<double>>>& A,
        std::vector<std::vector<std::complex<double>>>& B,
        std::vector<std::vector<std::complex<double>>>& C);
    static void CmpMultiply(
        size_t m, size_t n, size_t p,
        std::vector<std::vector<std::complex<double>>>& A,
        std::vector<std::vector<std::complex<double>>>& B,
        std::vector<std::vector<std::complex<double>>>& C);
    static void CmpAnticommutator(
        size_t n,
        std::vector<std::vector<std::complex<double>>>& A,
        std::vector<std::vector<std::complex<double>>>& B,
        std::vector<std::vector<std::complex<double>>>& C);
    static void CmpCommutator(
        size_t n,
        std::vector<std::vector<std::complex<double>>>& A,
        std::vector<std::vector<std::complex<double>>>& B,
        std::vector<std::vector<std::complex<double>>>& C);
    static void CmpAdjoint(
        size_t m, size_t n,
        std::vector<std::vector<std::complex<double>>>& Ac,
        std::vector<std::vector<std::complex<double>>>& Ad);
    static std::complex<double> CmpDeterminant(
        bool& failure, int n,
        std::vector<std::vector<std::complex<double>>>& A);
    static bool CmpGaussianElimination(
        int m, int n,
        std::vector<std::vector<std::complex<double>>>& A,
        std::vector<std::complex<double>>& b,
        std::vector<std::complex<double>>& x,
        std::vector<size_t>& pivot);
    static bool CmpGaussianFactor(
        int n, std::vector<std::vector<std::complex<double>>>& M,
        std::vector<size_t>& pivot);
    static bool CmpGaussianSolution(
        int n, std::vector<std::vector<std::complex<double>>>& M,
        std::vector<std::complex<double>>& b,
        std::vector<std::complex<double>>& x,
        std::vector<size_t>& pivot);
    static bool CmpSubstitution(
        int m, int n, std::vector<std::vector<std::complex<double>>>& M,
        std::vector<std::complex<double>>& b,
        std::vector<std::complex<double>>& x,
        std::vector<size_t>& pivot);
    static bool CmpInverse(
        int n, std::vector<std::vector<std::complex<double>>>& M,
        std::vector<std::vector<std::complex<double>>>& Mi);
    static void CmpCharPolyAndAdjoint(
        int n,
        std::vector<std::vector<std::complex<double>>>& C,
        std::vector<std::vector<std::complex<double>>>& I,
        std::vector<std::vector<std::complex<double>>>& M,
        std::vector<std::vector<std::complex<double>>>& adjoint,
        std::vector<std::complex<double>>& a);
    static void CmpMatrixKernel(
        int m, int n,
        std::vector<std::vector<std::complex<double>>>& M,
        std::vector<std::vector<std::complex<double>>>& X,
        size_t& r);
    static void CmpMatrixImage(
        int m, int n,
        std::vector<std::vector<std::complex<double>>>& M,
        std::vector<std::vector<std::complex<double>>>& N,
        std::vector<std::vector<std::complex<double>>>& X,
        int rank);
};
#include <vector>

class DblLinearAlgebra
{
public:
    static void DblPrintMatrix(
        int m, int n, std::vector<std::vector<double>>& A);
    static void DblAddition(
        size_t m, size_t n,
        std::vector<std::vector<double>>& A,
        std::vector<std::vector<double>>& B,
        std::vector<std::vector<double>>& C);
    static void DblSubtraction(
        size_t m, size_t n,
        std::vector<std::vector<double>>& A,
        std::vector<std::vector<double>>& B,
        std::vector<std::vector<double>>& C);
    static void DblMultiply(
        size_t m, size_t n, size_t p,
        std::vector<std::vector<double>>& A,
        std::vector<std::vector<double>>& B,
        std::vector<std::vector<double>>& C);
    static void DblAnticommutator(
        size_t n,
        std::vector<std::vector<double>>& A,
        std::vector<std::vector<double>>& B,
        std::vector<std::vector<double>>& C);
    static void DblCommutator(
        size_t n,
        std::vector<std::vector<double>>& A,
        std::vector<std::vector<double>>& B,
        std::vector<std::vector<double>>& C);
    static double DblDeterminant(
        bool& failure, int n,
        std::vector<std::vector<double>>& A);
    static bool DblGaussianElimination(
        int m, int n, std::vector<std::vector<double>>& A,
        std::vector<double>& b, std::vector<double>& x,
        std::vector<size_t>& pivot);
    static bool DblGaussianFactor(
        int n, std::vector<std::vector<double>>& M,
        std::vector<size_t>& pivot);
    static bool DblGaussianSolution(
        int n, std::vector<std::vector<double>>& M,
        std::vector<double>& b, std::vector<double>& x,
        std::vector<size_t>& pivot);
    static bool DblSubstitution(
        int n, std::vector<std::vector<double>>& M,
        std::vector<double>& b, std::vector<double>& x,
        std::vector<size_t>& pivot);
    static bool DblInverse(
        int n, std::vector<std::vector<double>>& M,
        std::vector<std::vector<double>>& A);
    static void DblCharPolyAndAdjoint(
        int n,
        std::vector<std::vector<double>>& C,
        std::vector<std::vector<double>>& I,
        std::vector<std::vector<double>>& M,
        std::vector<std::vector<double>>& adjoint,
        std::vector<double>& a);
    static void DblMatrixKernel(
        int m, int n,
        std::vector<std::vector<double>>& M,
        std::vector<std::vector<double>>& X,
        size_t& r);
    static void DblMatrixImage(
        int m, int n,
        std::vector<std::vector<double>>& M,
        std::vector<std::vector<double>>& N,
        std::vector<std::vector<double>>& X,
        int rank);
};
// Exercises from "Modern Quantum Chemistry An Introduction to Advanced
// Electronic Structure Theory" by Attila Szabo and Neil S. Ostlund
// https://chemistlibrary.wordpress.com/wp-content/uploads/2015/02/modern-quantum-chemistry.pdf
// Program (c) Tuesday, August 12, 2025 by James Pate Williams, Jr.

#include <complex>
#include <iomanip>
#include <iostream>
#include <vector>
#include "DblLinearAlgebra.h"
#include "CmpLinearAlgebra.h"

int main()
{
	double AArcb[3][3] = { { 2, 3, -1 }, { 4, 4, -3 }, { -2, 3, -1 } };
	double AArso[3][3] = { { 1, 1, 0 }, { 1, 2, 2 }, { 0, 2, -1 } };
	double BBrso[3][3] = { { 1, -1, 1 }, { -1, 0, 0 }, { 1, 0, 1} };
	double BBr[3][3] = { { 1, -1, 1 }, { -1 , 0, 0 }, { 1, 0, 1 } };
	double AAcr[3][3] = { { 1, 2, 3 }, { 4, 5, 6 }, { 7, 8, 9 } };
	double AAci[3][3] = { { 1, 1, 2 }, { 3, 0, 1 }, { 0, 2, 4 } };
	double BBcr[3][3] = { { 1, 0, 1 }, { 1 , 1, 0 }, { 0, 1, 1 } };
	double BBci[3][3] = { { 1, 2, 3 }, { 4, 5, 6 }, { 7, 8, 9 } };
	int m = 3, n = 3, p = 3;

	std::vector<double> br(3);
	std::vector<size_t> pivot(3);
	std::vector<std::vector<double>> Arcb(3, std::vector<double>(3));
	std::vector<std::vector<double>> Arso(3, std::vector<double>(3));
	std::vector<std::vector<double>> Brso(3, std::vector<double>(3));
	std::vector<std::vector<double>> Br(3, std::vector<double>(3));
	std::vector<std::vector<double>> Cr(3, std::vector<double>(3));
	std::vector<std::vector<double>> Ai(3, std::vector<double>(3));
	std::vector<std::vector<double>> Ari(3, std::vector<double>(3));
	std::vector<std::vector<std::complex<double>>> Ac(3,
		std::vector<std::complex<double>>(3));
	std::vector<std::vector<std::complex<double>>> Bc(3,
		std::vector<std::complex<double>>(3));
	std::vector<std::vector<std::complex<double>>> Cc(3,
		std::vector<std::complex<double>>(3));
	std::vector<std::vector<std::complex<double>>> Dc(3,
		std::vector<std::complex<double>>(3));
	std::vector<std::vector<std::complex<double>>> Ec(3,
		std::vector<std::complex<double>>(3));
	std::vector<std::vector<std::complex<double>>> Fc(3,
		std::vector<std::complex<double>>(3));
	std::vector<std::vector<std::complex<double>>> Gc(3,
		std::vector<std::complex<double>>(3));
	
	for (int i = 0; i < m; i++)
	{
		for (int j = 0; j < p; j++)
		{
			Arcb[i][j] = AArcb[i][j];
			Arso[i][j] = AArso[i][j];
			Brso[i][j] = BBrso[i][j];
			Ac[i][j]._Val[0] = AAcr[i][j];
			Ac[i][j]._Val[1] = AAci[i][j];
		}
	}

	for (int i = 0; i < p; i++)
	{
		for (int j = 0; j < n; j++)
		{
			Br[i][j] = BBr[i][j];
			Bc[i][j]._Val[0] = BBcr[i][j];
			Bc[i][j]._Val[1] = BBci[i][j];
		}
	}
	
	DblLinearAlgebra::DblMultiply(3, 3, 3, Arcb, Br, Cr);
	std::cout << "Ar * Br = Cr Conte & de Boor" << std::endl;
	DblLinearAlgebra::DblPrintMatrix(3, 3, Cr);
	std::cout << std::endl;
	CmpLinearAlgebra::CmpMultiply(3, 3, 3, Ac, Bc, Cc);
	std::cout << "Ac * Bc = Cc" << std::endl;
	CmpLinearAlgebra::CmpPrintMatrix(3, 3, Cc);
	std::cout << std::endl;
	// Exercise 1.2
	std::cout << "Exercise 1.2 page 5 Commutator" << std::endl;
	DblLinearAlgebra::DblCommutator(3, Arso, Brso, Cr);
	DblLinearAlgebra::DblPrintMatrix(3, 3, Cr);
	std::cout << std::endl;
	std::cout << "Exercise 1.2 page 5 Anticommutator" << std::endl;
	DblLinearAlgebra::DblAnticommutator(3, Arso, Brso, Cr);
	DblLinearAlgebra::DblPrintMatrix(3, 3, Cr);
	std::cout << std::endl;
	CmpLinearAlgebra::CmpAdjoint(3, 3, Cc, Dc);
	std::cout << "Exercise 1.3 page 6 Cc adjoint" << std::endl;
	CmpLinearAlgebra::CmpPrintMatrix(3, 3, Dc);
	std::cout << std::endl;
	CmpLinearAlgebra::CmpAdjoint(3, 3, Ac, Ec);
	CmpLinearAlgebra::CmpAdjoint(3, 3, Bc, Fc);
	CmpLinearAlgebra::CmpMultiply(3, 3, 3, Fc, Ec, Gc);
	std::cout << "Exercise 1.3 page 6 Bc adjoint * Ac adjoint" << std::endl;
	CmpLinearAlgebra::CmpPrintMatrix(3, 3, Gc);
	std::cout << std::endl;
	std::cout << "Ar matrix" << std::endl;
	DblLinearAlgebra::DblPrintMatrix(3, 3, Arcb);
	bool inv = DblLinearAlgebra::DblInverse(n, Arcb, Ai);
	std::cout << std::endl;
	std::cout << "Ar Conte & de Boor inverse = " << inv << std::endl;
	DblLinearAlgebra::DblPrintMatrix(3, 3, Ai);
	std::cout << std::endl;
	std::cout << "Ar * Ar inverse" << std::endl;
	DblLinearAlgebra::DblMultiply(3, 3, 3, Arcb, Ai, Ari);
	DblLinearAlgebra::DblPrintMatrix(3, 3, Ari);
	std::cout << std::endl;
	std::cout << "Ac" << std::endl;
	CmpLinearAlgebra::CmpPrintMatrix(3, 3, Ac);
	std::cout << std::endl;
	inv = CmpLinearAlgebra::CmpInverse(3, Ac, Bc);
	std::cout << "Ac inverse = " << inv << std::endl;
	CmpLinearAlgebra::CmpPrintMatrix(3, 3, Bc);
	CmpLinearAlgebra::CmpMultiply(3, 3, 3, Ac, Bc, Cc);
	std::cout << std::endl;
	std::cout << "Ac * AC inverse" << std::endl;
	CmpLinearAlgebra::CmpPrintMatrix(3, 3, Cc);
}

Blog Entry © Monday, August 11, 2025, by James Pate Williams, Jr. Van der Waals Interaction Between Two Hydrogen Atoms

Blog Entry © Sunday, August 10, 2025, First-Order Perturbation Treatment of the Helium Atom by James Pate Williams, Jr.

Blog Entry © Thursday, August 7, 2025, by James Pate Williams, Jr. Fender 12-String Acoustic-Electric Guitar MP3

The WAVE file was created on Friday, August 28, 2009, using Cakewalk’s SONAR Producer and no audio effects. Today, I opened the WAVE file’s project with SONAR Platinum and created an MP3 of the clean guitar (no effects). I probably had a capo set on the second fret.

Blog Entry © Thursday, August 7, 2025, z-Component of Cylindrical Velocity Based on an Equation in Classical Electrodynamics Second Edition © 1975 by John David Jackson

Blog Entry © Tuesday, August 5, 2025, by James Pate Williams, Jr. MP3 Names “To Catch an Escapee”

The MP3 “To Catch an Escapee” was created using the Digital Audio Workstation Cakewalk’s SONAR PLATIMUM. I used Cakewalk’s Strum Session 2 and the guitar effects console TH3. The console had Noise Reduction, Overdrive, Chorus, Digital Delay, Spring Reverb, Blackface ’65 Synthetic Amplifier with a Two Speaker Cabinet. The amp setup was based on the 1965 Fender Twin Reverb Amp. Of course, I have a real reissue of a 1965 Fender Twin Reverb Amp, which was purchased in the period 2008 to 2010 or a little before (?).

Blog Entry © Monday August 4, 2025, by James Pate Williams, Jr. Bessel Functions of the First and Second Kind, Their Derivatives and Zeros

Welcome to the Barre MP3

Saturday, August 2, 2025

Yesterday I wrote a new rhythm instrumental rock track entitled “Welcome to the Barre”. I use all barre chords. I utilized Cakewalk’s SONAR Platinum Digital Audio Workstation (DAW) with the Strum Session 2 software synthesizer. I also used the THS plugin. The effects used were a noise reducer, overdrive, chorus, digital delay, spring reverb, Blackface ’65 amplifier simulator with a two-speaker digital cabinet. The Blackface ’65 emulator is based on the 1965 Fender Twin Reverb Amp. I own a real ’65 reissue Fender Twin Reverb Amp.