125 lines
4.1 KiB
Objective-C
125 lines
4.1 KiB
Objective-C
//
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// MPElementaryFunctionTerm.m
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// MathKit
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//
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// Created by Kim Wittenburg on 11.10.14.
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// Copyright (c) 2014 Kim Wittenburg. All rights reserved.
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//
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#import "MPElementaryFunctionTerm.h"
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#import "MPParsedExpression.h"
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#import "MPMathRules.h"
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@implementation MPElementaryFunctionTerm {
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NSDecimalNumber *(^_function)(NSDecimalNumber *);
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}
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- (instancetype)initWithFunctionIdentifier:(NSString *)function
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term:(MPTerm *)term
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{
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self = [super init];
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if (self) {
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NSAssert(function != nil, @"function must not be nil.");
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NSAssert(term != nil, @"term must not be nil.");
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double (*func)(double);
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BOOL takesArc = NO;
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BOOL returnsArc = NO;
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if ([function isEqualToString:@"sin"]) {
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func = &sin;
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takesArc = YES;
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} else if ([function isEqualToString:@"cos"]) {
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func = &cos;
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takesArc = YES;
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} else if ([function isEqualToString:@"tan"]) {
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func = &tan;
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takesArc = YES;
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} else if ([function isEqualToString:@"asin"] || [function isEqualToString:@"arcsin"]) {
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func = &asin;
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returnsArc = YES;
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} else if ([function isEqualToString:@"acos"] || [function isEqualToString:@"arccos"]) {
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func = &acos;
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returnsArc = YES;
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} else if ([function isEqualToString:@"atan"] || [function isEqualToString:@"arctan"]) {
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func = &atan;
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returnsArc = YES;
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} else if ([function isEqualToString:@"lg"] || [function isEqualToString:@"log"]) {
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func = &log10;
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} else if ([function isEqualToString:@"ln"]) {
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func = &log;
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} else {
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NSAssert(true, @"function must be one of (sin, cos, tan, asin, arcsin, acos, arccos, atan, arctan, lg, log, ln).");
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}
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[self setFunction:func
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takesArcValue:takesArc
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returnsArcValue:returnsArc];
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_term = term;
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_functionIdentifier = function.copy;
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}
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return self;
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}
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- (void)setFunction:(double (*)(double))function
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takesArcValue:(BOOL)takesArc
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returnsArcValue:(BOOL)returnsArc
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{
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id __weak weakSelf = self;
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_function = ^(NSDecimalNumber *value){
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if (takesArc) {
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value = [weakSelf convertToRadiantsIfNecessary:value];
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}
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NSDecimalNumber *returnValue = [[NSDecimalNumber alloc] initWithDouble:function(value.doubleValue)];
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if (returnsArc) {
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returnValue = [weakSelf convertToDegreesIfNecessary:returnValue];
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}
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return returnValue;
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};
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}
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- (NSDecimalNumber *)convertToRadiantsIfNecessary:(NSDecimalNumber *)degrees
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{
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if ([MPMathRules sharedRules].isUsingDegrees) {
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// * M_PI / 180
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return [[degrees decimalNumberByMultiplyingBy:[[NSDecimalNumber alloc] initWithDouble:M_PI]] decimalNumberByDividingBy:[[NSDecimalNumber alloc] initWithInteger:180]];
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} else {
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return degrees;
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}
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}
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- (NSDecimalNumber *)convertToDegreesIfNecessary:(NSDecimalNumber *)radiants
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{
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if ([MPMathRules sharedRules].isUsingDegrees) {
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// * 180 / M_PI
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return [[radiants decimalNumberByMultiplyingBy:[[NSDecimalNumber alloc] initWithInteger:180]] decimalNumberByDividingBy:[[NSDecimalNumber alloc] initWithDouble:M_PI]];
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} else {
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return radiants;
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}
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}
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- (NSDecimalNumber *)doEvaluation:(NSError *__autoreleasing *)error
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{
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NSDecimalNumber *value = [self.term evaluate:error];
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if (!value) {
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return nil;
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}
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NSDecimalNumber *result = _function(value);
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if ([result isEqualToNumber:[NSDecimalNumber notANumber]]) {
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result = nil;
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if (error) {
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NSString *errorDescription = [NSString stringWithFormat:NSLocalizedString(@"%@ is not defined for the value %@.", nil), self.functionIdentifier, [value descriptionWithLocale:[NSLocale currentLocale]]];
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*error = [NSError errorWithDomain:MPMathKitErrorDomain
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code:102
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userInfo:@{NSLocalizedDescriptionKey: errorDescription}];
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}
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}
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return result;
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}
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@end
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