atan2

Calculate atan2 without std functions or C99

由 自闭症网瘾萝莉.ら 提交于 2019-12-18 17:27:52
问题 I am calculating angles from a 3-axis accelerometer, but my compiler doesn't have a atan or atan2 function. It has a reserved memory slot, but it calls a function i can't find in any files. My compiler is Keil µVision 4 running the ARMCC compiler. The compiles has the file math.h, but the function is extern and doesn't exist: extern _ARMABI double atan2(double /*y*/, double /*x*/); Is there a lib or function I can include that has the function arctan implemented? Or is there an alternative

Calculate atan2 without std functions or C99

由 ℡╲_俬逩灬. 提交于 2019-12-18 17:27:09
问题 I am calculating angles from a 3-axis accelerometer, but my compiler doesn't have a atan or atan2 function. It has a reserved memory slot, but it calls a function i can't find in any files. My compiler is Keil µVision 4 running the ARMCC compiler. The compiles has the file math.h, but the function is extern and doesn't exist: extern _ARMABI double atan2(double /*y*/, double /*x*/); Is there a lib or function I can include that has the function arctan implemented? Or is there an alternative

How to map atan2() to degrees 0-360

由 早过忘川 提交于 2019-12-17 05:43:10
问题 atan2(y,x) has that discontinuity at 180° where it switches to -180°..0° going clockwise. How do I map the range of values to 0°..360°? here is my code: CGSize deltaPoint = CGSizeMake(endPoint.x - startPoint.x, endPoint.y - startPoint.y); float swipeBearing = atan2f(deltaPoint.height, deltaPoint.width); I'm calculating the direction of a swiping touch event given the startPoint and endPoint, both XY point structs. The code is for the iPhone but any language that supports atan2f() will do.

How to map atan2() to degrees 0-360

由 こ雲淡風輕ζ 提交于 2019-12-17 05:42:50
问题 atan2(y,x) has that discontinuity at 180° where it switches to -180°..0° going clockwise. How do I map the range of values to 0°..360°? here is my code: CGSize deltaPoint = CGSizeMake(endPoint.x - startPoint.x, endPoint.y - startPoint.y); float swipeBearing = atan2f(deltaPoint.height, deltaPoint.width); I'm calculating the direction of a swiping touch event given the startPoint and endPoint, both XY point structs. The code is for the iPhone but any language that supports atan2f() will do.

math函数中的常用函数

由 守給你的承諾、 提交于 2019-12-16 00:56:03
绝对值函数 abs 求浮点数x的绝对值 fabs 余弦函数 cos 正弦函数 sin 正切函数 tan 反余弦函数 acos 反正弦函数 asin 反正切函数 atan 和 atan2 都是求反正切函数，如：有两个点 point(x1,y1), 和 point(x2,y2); 那么这两个点形成的斜率的角度计算方法分别是： float angle = atan( (y2-y1)/(x2-x1) ); 或 float angle = atan2( y2-y1, x2-x1 ); atan 和 atan2 区别： 参数的填写方式不同； atan2 的优点在于 如果 x2-x1等于0 依然可以计算，但是atan函数就会导致程序出错； 结论： atan 和 atan2函数，建议用 atan2函数； 开方 sqrt 求x的双曲正弦值 sinh 求x的双曲正切值 tanh 求x的双曲余弦值 cosh e的x次方 exp 计算x的y次幂 pow 求不小于x的最小整数 ceil 计算x/y的余数 fmod 把浮点数x分解成尾数和指数 frexp 对于给定的直角三角形的两个直角边，求其斜边的长度 hypot 装载浮点数 ldexp e为底对数 log 10为底对数 log10 把数分为指数和尾数 modf 来源： CSDN 作者： bloke_come 链接： https://blog.csdn

JavaScript atan2() function not giving expected results

由 人走茶凉 提交于 2019-12-14 03:45:20
问题 Normally, polar coordinates go from 0 to π to 2 π (just before 2 π really, as it equals 0 again). However, when using the JavaScript atan2() function, I'm getting a different, weird range: Cartesian X | Cartesian Y | Theta (θ) =========================================================== 1 | 0 | 0 (0 × π ) 1 | 1 | 0.7853981633974483 (0.25 × π ) 0 | 1 | 1.5707963267948966 (0.5 × π ) -1 | 1 | 2.356194490192345 (0.75 × π ) -1 | 0 | 3.141592653589793 (1 × π ) -1 | -1 | -2.356194490192345 (-0.75 × π

Math.Atan2 or class instance problem in C#

由 守給你的承諾、 提交于 2019-12-12 04:34:48
问题 Here is my problem (C#) : double Y = 0.0; double X = -21.0; double q1_Test = Math.Atan2(0.0, -21.0); // gives Math.Pi double q1_Test2 = Math.Atan2(( double)Y, (double)X); // gives Math.Pi double w1 = <SomeclassInstanceGlobalHere>.getW1(); // This is a class which updates a variable double w2 = <SomeclassInstanceGlobalHere>.getW2(); // This is a class which updates a variable double q1 = Math.Atan2(w2, w1); // ** gives -Math.Pi ** ??? //w2 shows 0.0 and w1 shows -21.0 When I get the values

help to calculate atan2 properly

由 旧巷老猫 提交于 2019-12-10 12:49:10
问题 I need to calculate the angle between lines. I need to calculate atan. So I am using such code static inline CGFloat angleBetweenLinesInRadians2(CGPoint line1Start, CGPoint line1End) { CGFloat dx = 0, dy = 0; dx = line1End.x - line1Start.x; dy = line1End.y - line1Start.y; NSLog(@"\ndx = %f\ndy = %f", dx, dy); CGFloat rads = fabs(atan2(dy, dx)); return rads; } But I can't get over 180 degrees(( After 179 deg going 178..160..150 and so on. I need to rotate on 360 degrees. How can I do it? What

How to compute directional angle between two 2D vectors in MatLab?

由 允我心安 提交于 2019-12-06 16:12:11
I am trying to implement a script to analyze some of my data. I have position information for three points (p1,p2,p3). I would like to find the angular displacement of point p3 from the vector p1p2, as in this picture: p3a, p3b, p3c, p3d show possible relative positions for p3. As shown, I would like the sign of the output angle to describe its relative position to vector p1p2. The code I am using is as follows (adapted to the diagram): v1 = p2 - p1; x1 = v1(1); y1 = v1(2); v2 = p1 - p3; x2 = v2(1); y2 = v2(2); angle = atan2d(x1*y2-y1*2,x1*x2+y1*y2); This works as desired when p3 is at p3a,

Calculating angles between line segments (Python) with math.atan2

由 六眼飞鱼酱① 提交于 2019-12-03 14:12:15
I am working on a spatial analysis problem and part of this workflow is to calculate the angle between connected line segments. Each line segment is composed of only two points, and each point has a pair of XY coordinates (Cartesian). Here is the image from GeoGebra. I am always interested in getting a positive angle in 0 to 180 range . However, I get all kind of angles depending on the order of vertices in input line segments. The input data I work with is provided as tuples of coordinates. Depending on the vertex creation order, the last/end point for each line segment can be different. Here
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