From: curt Date: Tue, 15 May 2001 21:07:41 +0000 (+0000) Subject: STL-ified the interpolation table so it is not size limited. X-Git-Url: https://git.mxchange.org/?a=commitdiff_plain;h=e145f903de06da82fc895258dc0de4a9b15c1258;p=simgear.git STL-ified the interpolation table so it is not size limited. --- diff --git a/simgear/math/interpolater.cxx b/simgear/math/interpolater.cxx index f0b0a453..d3d74350 100644 --- a/simgear/math/interpolater.cxx +++ b/simgear/math/interpolater.cxx @@ -38,10 +38,18 @@ SG_USING_STD(string); +// Constructor -- starts with an empty table. +SGInterpTable::SGInterpTable() + : size(0) +{ +} + // Constructor -- loads the interpolation table from the specified // file -SGInterpTable::SGInterpTable( const string& file ) { +SGInterpTable::SGInterpTable( const string& file ) + : size(0) +{ SG_LOG( SG_MATH, SG_INFO, "Initializing Interpolator for " << file ); sg_gzifstream in( file ); @@ -50,56 +58,62 @@ SGInterpTable::SGInterpTable( const string& file ) { exit(-1); } - size = 0; in >> skipcomment; while ( in ) { - if ( size < MAX_TABLE_SIZE ) { - in >> table[size][0] >> table[size][1]; - in >> skipws; - size++; - } else { - SG_LOG( SG_MATH, SG_ALERT, - "fgInterpolateInit(): Exceed max table size = " - << MAX_TABLE_SIZE ); - exit(-1); - } + double ind, dep; + in >> ind >> dep; + in >> skipws; + table.push_back(Entry(ind, dep)); + size++; } } +// Add an entry to the table. +void SGInterpTable::addEntry (double ind, double dep) +{ + table.push_back(Entry(ind,dep)); + size++; +} + + // Given an x value, linearly interpolate the y value from the table -double SGInterpTable::interpolate(double x) { +double SGInterpTable::interpolate(double x) const +{ int i; double y; + if (size == 0.0) + return 0.0; + i = 0; - while ( (x > table[i][0]) && (i < size) ) { - // cout << " i = " << i << " table[i][0] = " << table[i][0] << endl; + while ( (i < size) && (x > table[i].ind) ) { + // cout << " i = " << i << " table[i].ind = " << table[i].ind << endl; // cout << " size = " << size << endl; i++; } // printf ("i = %d ", i); - if ( (i == 0) && (x < table[0][0]) ) { + if ( (i == 0) && (x < table[0].ind) ) { SG_LOG( SG_MATH, SG_DEBUG, "interpolate(): lookup error, x to small = " << x ); - return table[0][1]; + return table[0].dep; } - // cout << " table[size-1][0] = " << table[size-1][0] << endl; - if ( x > table[size-1][0] ) { + // cout << " table[size-1].ind = " << table[size-1].ind << endl; + if ( x > table[size-1].ind ) { SG_LOG( SG_MATH, SG_DEBUG, "interpolate(): lookup error, x to big = " << x ); - return table[size-1][1]; + return table[size-1].dep; } // y = y1 + (y0 - y1)(x - x1) / (x0 - x1) - y = table[i][1] + - ( (table[i-1][1] - table[i][1]) * - (x - table[i][0]) ) / - (table[i-1][0] - table[i][0]); + y = table[i].dep + + ( (table[i-1].dep - table[i].dep) * + (x - table[i].ind) ) / + (table[i-1].ind - table[i].ind); return(y); } diff --git a/simgear/math/interpolater.hxx b/simgear/math/interpolater.hxx index 501e4ac8..12ce6f3c 100644 --- a/simgear/math/interpolater.hxx +++ b/simgear/math/interpolater.hxx @@ -36,10 +36,12 @@ #include +#include +SG_USING_STD(vector); + #include STL_STRING SG_USING_STD(string); -#define MAX_TABLE_SIZE 32 /** * A class that provids a simple linear 2d interpolation lookup table. @@ -48,23 +50,49 @@ SG_USING_STD(string); * variable can be anything. */ class SGInterpTable { + + struct Entry + { + Entry () + : ind(0.0L), dep(0.0L) {} + Entry (double independent, double dependent) + : ind(independent), dep(dependent) {} + double ind; + double dep; + }; + int size; - double table[MAX_TABLE_SIZE][2]; + vector table; public: + /** + * Constructor. Creates a new, empty table. + */ + SGInterpTable(); + /** * Constructor. Loads the interpolation table from the specified file. * @param file name of interpolation file */ SGInterpTable( const string& file ); + + /** + * Add an entry to the table, extending the table's length. + * + * @param ind The independent variable. + * @param dep The dependent variable. + */ + void addEntry (double ind, double dep); + + /** * Given an x value, linearly interpolate the y value from the table. * @param x independent variable * @return interpolated dependent variable */ - double interpolate(double x); + double interpolate(double x) const; /** Destructor */ ~SGInterpTable();