SCIP
Solving Constraint Integer Programs
Solving Constraint Integer Programs
commonly used numerical methods
Modules | |
| Computations With Tolerances | |
| methods used by the majority of operations involving floating-point computations in SCIP | |
Macros | |
| #define | SCIPisFinite(x) ((x) == (x)) |
| #define SCIPisFinite | ( | x | ) | ((x) == (x)) |
Definition at line 1768 of file pub_misc.h.
Referenced by addConcaveEstimatorBivariate(), addConcaveEstimatorUnivariate(), addIntervalGradientEstimator(), addLinearization(), computeViolation(), evalFunctionGradient(), F77_FUNC(), generate1ConvexIndefiniteUnderestimator(), generate1ConvexIndefiniteUnderestimatorAtBoundary(), generate1ConvexIndefiniteUnderestimatorInTheInteriorPatternA(), generate1ConvexIndefiniteUnderestimatorInTheInteriorPatternB(), generateConvexConcaveEstimator(), generateConvexConcaveUnderestimator(), generateEstimatingHyperplane(), generateLinearizationCut(), generateOrthogonal_lx_ly_Underestimator(), generateOrthogonal_lx_uy_Underestimator(), generateOverestimatingHyperplaneCut(), generateUnderestimatorParallelYFacets(), hessLagAddExprtree(), lifting(), readExpression(), readLinearCoefs(), readMultIncr(), SCIPexprgraphSimplify(), SCIPnlpiOracleEvalJacobian(), SCIPsolSetVal(), setupStart(), and solveDerivativeEquation().
| SCIP_Real SCIPcalcMachineEpsilon | ( | void | ) |
returns the machine epsilon: the smallest number eps > 0, for which 1.0 + eps > 1.0
Definition at line 8425 of file misc.c.
References eps, and SCIP_Real.
Referenced by SCIPrealHashCode().
returns the next representable value of from in the direction of to
| from | value from which the next representable value should be returned |
| to | direction in which the next representable value should be returned |
Definition at line 8691 of file misc.c.
Referenced by initSolve(), SCIPintervalExp(), SCIPintervalLog(), SCIPintervalPowerScalar(), SCIPintervalPowerScalarScalar(), SCIPintervalSignPowerScalar(), SCIPintervalSolveUnivariateQuadExpressionPositiveAllScalar(), SCIPintervalSquareRoot(), and SCIPrealHashCode().
| SCIP_Longint SCIPcalcGreComDiv | ( | SCIP_Longint | val1, |
| SCIP_Longint | val2 | ||
| ) |
calculates the greatest common divisor of the two given values
| val1 | first value of greatest common devisor calculation |
| val2 | second value of greatest common devisor calculation |
Definition at line 8448 of file misc.c.
Referenced by deleteRedundantVars(), normalizeCumulativeCondition(), presolveTryAddLinearReform(), SCIPcalcIntegralScalar(), SCIPcalcSmaComMul(), SCIPprobScaleObj(), SCIPrealHashCode(), SCIProwCalcIntegralScalar(), SCIPsolveKnapsackExactly(), simplifyInequalities(), and tryAggregateIntVars().
| SCIP_Longint SCIPcalcSmaComMul | ( | SCIP_Longint | val1, |
| SCIP_Longint | val2 | ||
| ) |
calculates the smallest common multiple of the two given values
| val1 | first value of smallest common multiple calculation |
| val2 | second value of smallest common multiple calculation |
Definition at line 8700 of file misc.c.
References SCIP_Longint, and SCIPcalcGreComDiv().
Referenced by SCIPrealHashCode(), and tryAggregateIntVars().
| SCIP_Longint SCIPcalcBinomCoef | ( | int | n, |
| int | m | ||
| ) |
calculates a binomial coefficient n over m, choose m elements out of n, maximal value will be 33 over 16 (because the n=33 is the last line in the Pascal's triangle where each entry fits in a 4 byte value), an error occurs due to big numbers or an negative value m (and m < n) and -1 will be returned
| n | number of different elements |
| m | number to choose out of the above |
Definition at line 9530 of file misc.c.
References SCIP_Longint, SCIP_LONGINT_MAX, and SCIP_Real.
Referenced by SCIPrealHashCode().
| SCIP_Bool SCIPrealToRational | ( | SCIP_Real | val, |
| SCIP_Real | mindelta, | ||
| SCIP_Real | maxdelta, | ||
| SCIP_Longint | maxdnom, | ||
| SCIP_Longint * | nominator, | ||
| SCIP_Longint * | denominator | ||
| ) |
converts a real number into a (approximate) rational representation, and returns TRUE iff the conversion was successful
| val | real value r to convert into rational number |
| mindelta | minimal allowed difference r - q of real r and rational q = n/d |
| maxdelta | maximal allowed difference r - q of real r and rational q = n/d |
| maxdnom | maximal denominator allowed |
| nominator | pointer to store the nominator n of the rational number |
| denominator | pointer to store the denominator d of the rational number |
Definition at line 8721 of file misc.c.
References EPSFLOOR, EPSGT, FALSE, REALABS, SCIP_Longint, SCIP_LONGINT_MAX, SCIP_Real, and TRUE.
Referenced by prettifyConss(), SCIPcalcIntegralScalar(), SCIPfindSimpleRational(), SCIPrealHashCode(), SCIProwCalcIntegralScalar(), and tryAggregateIntVars().
| SCIP_RETCODE SCIPcalcIntegralScalar | ( | SCIP_Real * | vals, |
| int | nvals, | ||
| SCIP_Real | mindelta, | ||
| SCIP_Real | maxdelta, | ||
| SCIP_Longint | maxdnom, | ||
| SCIP_Real | maxscale, | ||
| SCIP_Real * | intscalar, | ||
| SCIP_Bool * | success | ||
| ) |
tries to find a value, such that all given values, if scaled with this value become integral in relative allowed difference in between mindelta and maxdelta
| vals | values to scale |
| nvals | number of values to scale |
| mindelta | minimal relative allowed difference of scaled coefficient s*c and integral i |
| maxdelta | maximal relative allowed difference of scaled coefficient s*c and integral i |
| maxdnom | maximal denominator allowed in rational numbers |
| maxscale | maximal allowed scalar |
| intscalar | pointer to store scalar that would make the coefficients integral, or NULL |
| success | stores whether returned value is valid |
Definition at line 8881 of file misc.c.
References EPSEQ, FALSE, isIntegralScalar(), nscalars, REALABS, SCIP_Bool, SCIP_DEFAULT_EPSILON, SCIP_INVALID, SCIP_Longint, SCIP_OKAY, SCIP_Real, SCIP_REAL_MAX, SCIPcalcGreComDiv(), SCIPdebugMessage, SCIPrealToRational(), and TRUE.
Referenced by buildFlowCover(), cutTightenCoefs(), cutTightenCoefsQuad(), SCIPprobScaleObj(), SCIPrealHashCode(), SCIPseparateRelaxedKnapsack(), and transformNonIntegralRow().
| SCIP_Bool SCIPfindSimpleRational | ( | SCIP_Real | lb, |
| SCIP_Real | ub, | ||
| SCIP_Longint | maxdnom, | ||
| SCIP_Longint * | nominator, | ||
| SCIP_Longint * | denominator | ||
| ) |
given a (usually very small) interval, tries to find a rational number with simple denominator (i.e. a small number, probably multiplied with powers of 10) out of this interval; returns TRUE iff a valid rational number inside the interval was found
| lb | lower bound of the interval |
| ub | upper bound of the interval |
| maxdnom | maximal denominator allowed for resulting rational number |
| nominator | pointer to store the nominator n of the rational number |
| denominator | pointer to store the denominator d of the rational number |
Definition at line 9085 of file misc.c.
References SCIP_Real, SCIPintervalGetRoundingMode(), SCIPintervalHasRoundingControl(), SCIPintervalSetRoundingMode(), SCIPintervalSetRoundingModeDownwards(), and SCIPrealToRational().
Referenced by SCIPrealHashCode(), and SCIPselectSimpleValue().
| SCIP_Real SCIPselectSimpleValue | ( | SCIP_Real | lb, |
| SCIP_Real | ub, | ||
| SCIP_Longint | maxdnom | ||
| ) |
given a (usually very small) interval, selects a value inside this interval; it is tried to select a rational number with simple denominator (i.e. a small number, probably multiplied with powers of 10); if no valid rational number inside the interval was found, selects the central value of the interval
| lb | lower bound of the interval |
| ub | upper bound of the interval |
| maxdnom | maximal denominator allowed for resulting rational number |
Definition at line 9126 of file misc.c.
References getRand(), MAX, SCIP_Bool, SCIP_Longint, SCIP_RAND_MAX, SCIP_Real, SCIPdebugMessage, SCIPdebugPrintf, and SCIPfindSimpleRational().
Referenced by presolveTryAddLinearReform(), SCIP_DECL_PRESOLEXEC(), SCIPanalyzeDeductionsProbing(), and SCIPrealHashCode().
returns the relative difference: (val1-val2)/max(|val1|,|val2|,1.0)
| val1 | first value to be compared |
| val2 | second value to be compared |
Definition at line 10289 of file misc.c.
References REALABS, and SCIP_Real.
Referenced by buildFlowCover(), checkCons(), checkCumulativeCondition(), checkOrigPbCons(), checkSolOrig(), computeViolation(), getIntegralScalar(), isIntegralScalar(), priceAndCutLoop(), SCIP_DECL_CONSCHECK(), SCIPbranchExecExtern(), SCIPbranchGetBranchingPoint(), SCIPconcsolverSync(), SCIPcutGenerationHeuristicCMIR(), SCIPexprgraphSimplify(), SCIPexprtreeSimplify(), SCIPtreeBranchVar(), SCIPtreeBranchVarNary(), SCIPvalidateSolve(), and updateBestCandidate().
| SCIP_Real SCIPcomputeGap | ( | SCIP_Real | eps, |
| SCIP_Real | inf, | ||
| SCIP_Real | primalbound, | ||
| SCIP_Real | dualbound | ||
| ) |
computes the gap from the primal and the dual bound
| eps | the value treated as zero |
| inf | the value treated as infinity |
| primalbound | the primal bound |
| dualbound | the dual bound |
Definition at line 10307 of file misc.c.
References EPSEQ, EPSZ, SCIP_Interval::inf, REALABS, and SCIP_Real.
Referenced by SCIPgetConcurrentGap(), and SCIPgetGap().