math

问题 I am trying to convert a given double into scientific notation, and running into some problems. I cant seem to find much documentation on how to do it either. Currently I am using: var val = 500 var numberFormatter = NSNumberFormatter() numberFormatter.numberStyle = NSNumberFormatterStyle.ScientificStyle let number = numberFormatter.numberFromString("\(val)") println(number as Double?) // Prints optional(500) instead of optional(5e+2) What am I doing wrong? 回答1: You can set NumberFormatter

问题 I am looking for an efficient algorithm to find nth root of a number. The answer must be an integer. I have found that newtons method and bisection method are popular methods. Are there any efficient and simple methods for integer output? 回答1: #include <math.h> inline int root(int input, int n) { return round(pow(input, 1./n)); } This works for pretty much the whole integer range (as IEEE754 8-byte double s can represent the whole 32-bit int range exactly, which are the representations and

问题 I am looking for an efficient algorithm to find nth root of a number. The answer must be an integer. I have found that newtons method and bisection method are popular methods. Are there any efficient and simple methods for integer output? 回答1: #include <math.h> inline int root(int input, int n) { return round(pow(input, 1./n)); } This works for pretty much the whole integer range (as IEEE754 8-byte double s can represent the whole 32-bit int range exactly, which are the representations and

问题 What is the Mathematical formula for CUMIPMT function of EXCEL(how it is calculated)? I want to calculate it mathematically. Please Help 回答1: The implementation of CUMIPMT in Excel is impossible for us to provide seeing as Excel is not open-source. However numerous results show up in a Google search such as this implementation in Javascript, this other implementation also in Javascript, or PHPExcel's implementation in PHP. The closest result would probably be to look at Open Office's C++

问题 What is the Mathematical formula for CUMIPMT function of EXCEL(how it is calculated)? I want to calculate it mathematically. Please Help 回答1: The implementation of CUMIPMT in Excel is impossible for us to provide seeing as Excel is not open-source. However numerous results show up in a Google search such as this implementation in Javascript, this other implementation also in Javascript, or PHPExcel's implementation in PHP. The closest result would probably be to look at Open Office's C++

问题 What is the Mathematical formula for CUMIPMT function of EXCEL(how it is calculated)? I want to calculate it mathematically. Please Help 回答1: The implementation of CUMIPMT in Excel is impossible for us to provide seeing as Excel is not open-source. However numerous results show up in a Google search such as this implementation in Javascript, this other implementation also in Javascript, or PHPExcel's implementation in PHP. The closest result would probably be to look at Open Office's C++

问题 This question already has answers here : How to make smooth movement in pygame (2 answers) Closed 4 months ago . I have two blocks, one is controlled by the user. When i move my block, i want the other block to follow me. I tried doing something like this def follow(): distance = math.hypot(abs(m.x - p.x), abs(m.y - p.y)) angle_radians = math.atan2(abs(m.y - p.y), abs(m.x - p.x)) if distance != 0: p.y += math.sin(angle_radians) p.x += math.cos(angle_radians) However, the block ends up moving

问题 This question already has answers here : How to make smooth movement in pygame (2 answers) Closed 4 months ago . I have two blocks, one is controlled by the user. When i move my block, i want the other block to follow me. I tried doing something like this def follow(): distance = math.hypot(abs(m.x - p.x), abs(m.y - p.y)) angle_radians = math.atan2(abs(m.y - p.y), abs(m.x - p.x)) if distance != 0: p.y += math.sin(angle_radians) p.x += math.cos(angle_radians) However, the block ends up moving

问题 I want to implement for a step function in numpy with the definition: 回答1: Since the other answer does not implement the function in the question, here is a correct soluton: import numpy as np import matplotlib.pyplot as plt x= np.linspace(0., 50., 1001) f = lambda x0, x1: np.piecewise(x, [x < x0, (x >= x0) & (x <= x1), x > x1], [0., lambda x: x/x0, 1.]) plt.plot(x, f(10, 30)) plt.show() 来源： https://stackoverflow.com/questions/57516274/step-function-with-linear-inteval-in-numpy

问题 I want to implement for a step function in numpy with the definition: 回答1: Since the other answer does not implement the function in the question, here is a correct soluton: import numpy as np import matplotlib.pyplot as plt x= np.linspace(0., 50., 1001) f = lambda x0, x1: np.piecewise(x, [x < x0, (x >= x0) & (x <= x1), x > x1], [0., lambda x: x/x0, 1.]) plt.plot(x, f(10, 30)) plt.show() 来源： https://stackoverflow.com/questions/57516274/step-function-with-linear-inteval-in-numpy