eseries.cpp

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/*
 * This program source code file
 * is part of KiCad, a free EDA CAD application.
 *
 * Copyright (C) 2020 <[email protected]>
 * Copyright (C) 2021-2023 KiCad Developers, see AUTHORS.txt for contributors.
 *
 * This program is free software: you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation, either version 3 of the License, or (at your
 * option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program. If not, see <http://www.gnu.org/licenses/>.
 */
 
#include <array>
#include <algorithm>
#include <limits>
#include "eseries.h"
 
/*
 * If BENCHMARK is defined, any 4R E12 calculations will print its execution time to console
 * My Hasswell Enthusiast reports 225 mSec what are reproducible within plusminus 2 percent
 */
//#define BENCHMARK
 
#ifdef BENCHMARK
#include <profile.h>
#endif
 
 
// Return a string from aValue (aValue is expected in ohms)
// If aValue < 1000 the returned string is aValue with unit = R
// If aValue >= 1000 the returned string is aValue/1000 with unit = K
// with notation similar to 2K2
// If aValue >= 1e6 the returned string is aValue/1e6 with unit = M
// with notation = 1M
static std::string strValue( double aValue )
{
 std::string result;
 
 if( aValue < 1000.0 )
 {
 result = std::to_string( static_cast<int>( aValue ) );
 result += 'R';
 }
 else
 {
 double div = 1e3;
 char unit = 'K';
 
 if( aValue >= 1e6 )
 {
 div = 1e6;
 unit = 'M';
 }
 
 aValue /= div;
 
 int integer = static_cast<int>( aValue );
 result = std::to_string(integer);
 result += unit;
 
 // Add mantissa: 1 digit, suitable for series up to E24
 double mantissa = aValue - integer;
 
 if( mantissa > 0 )
 result += std::to_string( static_cast<int>( (mantissa*10)+0.5 ) );
 }
 
 return result;
}
 
 
E_SERIES::E_SERIES()
{
 // Build the list of available resistor values in each En serie
 double listValuesE1[] = { E1_VALUES };
 double listValuesE3[] = { E3_VALUES };
 double listValuesE6[] = { E6_VALUES };
 double listValuesE12[] = { E12_VALUES };
 double listValuesE24[] = { E24_VALUES };
 // buildSeriesData must be called in the order of En series, because
 // the list of series is expected indexed by En for the serie En
 buildSeriesData( listValuesE1 );
 buildSeriesData( listValuesE3 );
 buildSeriesData( listValuesE6 );
 buildSeriesData( listValuesE12 );
 int count = buildSeriesData( listValuesE24 );
 
 // Reserve a buffer for intermediate calculations:
 // the buffer size is 2*count*count to store all combinaisons of 2 values
 // there are 2*count*count = 29282 combinations for E24
 int bufsize = 2*count*count;
 m_combined_table.reserve( bufsize );
 
 // Store predefined R_DATA items.
 for( int ii = 0; ii < bufsize; ii++ )
 m_combined_table.emplace_back( "", 0.0 );
}
 
 
int E_SERIES::buildSeriesData( const double aList[] )
{
 double curr_decade = FIRST_VALUE;
 int count = 0;
 
 std::vector<R_DATA> curr_list;
 
 for( ; ; )
 {
 double curr_r = LAST_VALUE;
 
 for( int ii = 0; ; ii++ )
 {
 if( aList[ii] == 0.0 ) // End of list
 break;
 
 curr_r = curr_decade * aList[ii];
 curr_list.emplace_back( strValue( curr_r ), curr_r );
 count++;
 
 if( curr_r >= LAST_VALUE )
 break;
 }
 
 if( curr_r >= LAST_VALUE )
 break;
 
 curr_decade *= 10;
 }
 
 m_tables.push_back( std::move( curr_list ) );
 
 return count;
}
 
 
void E_SERIES::Exclude( double aValue )
{
 if( aValue != 0.0 ) // if there is a value to exclude other than a wire jumper
 {
 for( R_DATA& i : m_tables[m_series] ) // then search it in the selected E-Series table
 {
 if( i.e_value == aValue ) // if the value to exclude is found
 i.e_use = false; // disable its use
 }
 }
}
 
 
void E_SERIES::simple_solution( uint32_t aSize )
{
 uint32_t i;
 
 m_results.at( S2R ).e_value = std::numeric_limits<double>::max(); // assume no 2R solution or max deviation
 
 for( i = 0; i < aSize; i++ )
 {
 if( std::abs( m_combined_table.at( i ).e_value - m_required_value ) < std::abs( m_results.at( S2R ).e_value ) )
 {
 m_results[S2R].e_value = m_combined_table[ i ].e_value - m_required_value; // save signed deviation in Ohms
 m_results[S2R].e_name = m_combined_table[ i ].e_name; // save combination text
 m_results[S2R].e_use = true; // this is a possible solution
 }
 }
}
 
 
void E_SERIES::combine4( uint32_t aSize )
{
 uint32_t i,j;
 double tmp;
 
 m_results[S4R].e_use = false; // disable 4R solution, until
 m_results[S4R].e_value = m_results[S3R].e_value; // 4R becomes better than 3R solution
 
#ifdef BENCHMARK
 PROF_TIMER timer; // start timer to count execution time
#endif
 
 for( i = 0; i < aSize; i++ ) // 4R search outer loop
 { // scan valid intermediate 2R solutions
 for( j = 0; j < aSize; j++ ) // inner loop combines all with itself
 {
 tmp = m_combined_table[i].e_value + m_combined_table[j].e_value; // calculate 2R+2R serial
 tmp -= m_required_value; // calculate 4R deviation
 
 if( std::abs( tmp ) < std::abs( m_results.at(S4R).e_value ) ) // if new 4R is better
 {
 m_results[S4R].e_value = tmp; // save amount of benefit
 std::string s = "( ";
 s.append( m_combined_table[i].e_name ); // mention 1st 2 component
 s.append( " ) + ( " ); // in series
 s.append( m_combined_table[j].e_name ); // with 2nd 2 components
 s.append( " )" );
 m_results[S4R].e_name = s; // save the result and
 m_results[S4R].e_use = true; // enable for later use
 }
 
 tmp = ( m_combined_table[i].e_value * m_combined_table[j].e_value ) /
 ( m_combined_table[i].e_value + m_combined_table[j].e_value ); // calculate 2R|2R parallel
 tmp -= m_required_value; // calculate 4R deviation
 
 if( std::abs( tmp ) < std::abs( m_results[S4R].e_value ) ) // if new 4R is better
 {
 m_results[S4R].e_value = tmp; // save amount of benefit
 std::string s = "( ";
 s.append( m_combined_table[i].e_name ); // mention 1st 2 component
 s.append( " ) | ( " ); // in parallel
 s.append( m_combined_table[j].e_name ); // with 2nd 2 components
 s.append( " )" );
 m_results[S4R].e_name = s;  // save the result
 m_results[S4R].e_use = true; // enable later use
 }
 }
 }
 
#ifdef BENCHMARK
 printf( "Calculation time = %d mS", timer.msecs() );
 fflush( 0 );
#endif
}
 
 
void E_SERIES::NewCalc()
{
 for( R_DATA& i : m_combined_table )
 i.e_use = false; // before any calculation is done, assume that
 
 for( R_DATA& i : m_results )
 i.e_use = false; // no combinations and no results are available
 
 for( R_DATA& i : m_tables[m_series])
 i.e_use = true; // all selected E-values available
}
 
 
uint32_t E_SERIES::combine2()
{
 uint32_t combi2R = 0; // target index counts calculated 2R combinations
 std::string s;
 
 for( const R_DATA& i : m_tables[m_series] ) // outer loop to sweep selected source lookup table
 {
 if( i.e_use )
 {
 for( const R_DATA& j : m_tables[m_series] ) // inner loop to combine values with itself
 {
 if( j.e_use )
 {
 m_combined_table[combi2R].e_use = true;
 m_combined_table[combi2R].e_value = i.e_value + j.e_value; // calculate 2R serial
 s = i.e_name;
 s.append( " + " );
 m_combined_table[combi2R].e_name = s.append( j.e_name);
 combi2R++; // next destination
 m_combined_table[combi2R].e_use = true; // calculate 2R parallel
 m_combined_table[combi2R].e_value = i.e_value * j.e_value / ( i.e_value + j.e_value );
 s = i.e_name;
 s.append( " | " );
 m_combined_table[combi2R].e_name = s.append( j.e_name );
 combi2R++; // next destination
 }
 }
 }
 }
 return combi2R;
}
 
 
void E_SERIES::combine3( uint32_t aSize )
{
 uint32_t j = 0;
 double tmp = 0; // avoid warning for being uninitialized
 std::string s;
 
 m_results[S3R].e_use = false; // disable 3R solution, until 3R
 m_results[S3R].e_value = m_results[S2R].e_value; // becomes better than 2R solution
 
 for( const R_DATA& i : m_tables[m_series] ) // 3R Outer loop to selected primary E series table
 {
 if( i.e_use ) // skip all excluded values
 {
 for( j = 0; j < aSize; j++ ) // inner loop combines with all 2R intermediate
 { // results R+2R serial combi
 tmp = m_combined_table[j].e_value + i.e_value;
 tmp -= m_required_value; // calculate deviation
 
 if( std::abs( tmp ) < std::abs( m_results[S3R].e_value ) ) // compare if better
 { // then take it
 s = i.e_name; // mention 3rd component
 s.append( " + ( " ); // in series
 s.append( m_combined_table[j].e_name ); // with 2R combination
 s.append( " )" );
 m_results[S3R].e_name = s; // save S3R result
 m_results[S3R].e_value = tmp; // save amount of benefit
 m_results[S3R].e_use = true; // enable later use
 }
 
 tmp = i.e_value * m_combined_table[j].e_value /
 ( i.e_value + m_combined_table[j].e_value ); // calculate R + 2R parallel
 tmp -= m_required_value; // calculate deviation
 
 if( std::abs( tmp ) < std::abs( m_results[S3R].e_value ) ) // compare if better
 { // then take it
 s = i.e_name; // mention 3rd component
 s.append( " | ( " ); // in parallel
 s.append( m_combined_table[j].e_name ); // with 2R combination
 s.append( " )" );
 m_results[S3R].e_name = s;
 m_results[S3R].e_value = tmp; // save amount of benefit
 m_results[S3R].e_use = true; // enable later use
 }
 }
 }
 }
 
 // If there is a 3R result with remaining deviation consider to search a possibly better
 // 4R solution
 // calculate 4R for small series always
 if( m_results[S3R].e_use && tmp )
 combine4( aSize );
}
 
 
void E_SERIES::Calculate()
{
 uint32_t no_of_2Rcombi = 0;
 
 no_of_2Rcombi = combine2(); // combine all 2R combinations for selected E serie
 simple_solution( no_of_2Rcombi ); // search for simple 2 component solution
 
 if( m_results[S2R].e_value ) // if simple 2R result is not exact
 combine3( no_of_2Rcombi ); // continiue searching for a possibly better solution
 
 strip3();
 strip4();
}
 
 
void E_SERIES::strip3()
{
 std::string s;
 
 if( m_results[S3R].e_use ) // if there is a 3 term result available
 { // what is connected either by two "|" or by 3 plus
 s = m_results[S3R].e_name;
 
 if( ( std::count( s.begin(), s.end(), '+' ) == 2 )
 || ( std::count( s.begin(), s.end(), '|' ) == 2 ) )
 { // then strip one pair of braces
 s.erase( s.find( "( " ), 2 ); // it is known sure, this is available
 s.erase( s.find( " )" ), 2 ); // in any unstripped 3R result term
 m_results[S3R].e_name = s; // use stripped result
 }
 }
}
 
 
void E_SERIES::strip4()
{
 std::string s;
 
 if( m_results[S4R].e_use ) // if there is a 4 term result available
 { // what are connected either by 3 "+" or by 3 "|"
 s = m_results[S4R].e_name;
 
 if( ( std::count( s.begin(), s.end(), '+' ) == 3 )
 || ( std::count( s.begin(), s.end(), '|' ) == 3 ) )
 { // then strip two pair of braces
 s.erase( s.find( "( " ), 2 ); // it is known sure, they are available
 s.erase( s.find( " )" ), 2 ); // in any unstripped 4R result term
 s.erase( s.find( "( " ), 2 );
 s.erase( s.find( " )" ), 2 );
 m_results[S4R].e_name = s; // use stripped result
 }
 }
}