numerical

问题 I've this dataset: 12363 111111 12363 222222 12363 3456 12364 2895 12364 257363 12364 246291 12364 243701 12364 243699 I would like to sort this by first column, numerical value, reverse and by second column, numerical value, reverse. Result would be: 12364 257363 12364 246291 12364 243701 12364 243699 12364 2895 12363 222222 12363 111111 12363 3456 I tried, sort -rn sort -rnk1,2 sort -rg sort -rgk1,2 But somehow all of these gives back for the second column a wrong order (not numerical, but

问题 My purpose is to call some C function from my C++ code and pass some C++ objects. In fact I am using a integration routine from the GSL libray(written in C), see this link, My code snippet: // main.cpp #include <stdio.h> #include <gsl/gsl_integration.h> #include <myclass.h> /* my test function. */ double testfunction ( double x , void *param ) { myclass *bar=static_cast<myclass*>(param); /*** do something with x and bar***/ return val; } int main ( int argc , char *argv[] ) { gsl_function F;

问题 I have a json object which I converted to dynamic C# object with help of this answer. It works just fine, but trouble is that this object has numerical keys. For instance, var jsStr = "{address:{"100": {...}}}"; So I can't wirte dynObj.address.100 And, as I know, I can't use indexers to get this object like this dynObj.address["100"] Please explain to me how I can get this working. 回答1: As far as I can see from the source code he resolves the properties through a private dictionary, so you

问题 Is it a bad practice to overload global operator == and != for floating points ? I'm using fast floating-points in a game environement, and i was thinking about using fuzzy comparison everywhere as i can't imagine a situation where i don't expect extremely close numbers not to be equals. Any advice ? 回答1: Other posts mentioned technical problems, from another perspective: Its a bad practice because nobody expects these operators to be overloaded, while reasonable people will expect an

问题 I've written a program about color detection by using python. But always there's an error around the 'Erode' sentence. Here's part of my program. Thank you. # Convert the image to a Numpy array since most cv2 functions # require Numpy arrays. frame = np.array(frame, dtype=np.uint8) threshold = 0.05 #blur the image frame=cv2.blur(frame, (5,5)) #Convert from BGR to HSV hsv = cv2.cvtColor(frame, cv2.COLOR_BGR2HSV) #split into 3 h, s, v= cv2.split(hsv) #red color s = cv2.threshold(h, 15, 1, cv2

问题 On my 64-bit Debian/Lenny system (4GByte RAM + 4GByte swap partition) I can successfully do: v=array(10000*random([512,512,512]),dtype=np.int16) f=fftn(v) but with f being a np.complex128 the memory consumption is shocking, and I can't do much more with the result (e.g modulate the coefficients and then f=ifftn(f) ) without a MemoryError traceback. Rather than installing some more RAM and/or expanding my swap partitions, is there some way of controlling the scipy/numpy "default precision" and

问题 I want to compute: result = SUM (c=0,N) { V_ck * U_lc * S_c } But my 2D matrices are indexed as 1D and stored as column major. I am trying: float *A,*B; int M,N; A = (float *) malloc( M * N * sizeof(float) ); B = (float *) malloc( M * sizeof(float) ); float *S = (float *)malloc( N * sizeof( float) ); float *U = (float *)malloc( M * M * sizeof( float) ); float *V = (float *)malloc( N * N * sizeof( float) ); float * result = (float *) malloc( M * N * sizeof(float) ); float thesum=0; for (int k

问题 I have the following function which I would like to numerically integrate using python, Using scipy, I have written this code: def voigt(a,u): fi = 1 er = Cerfc(a)*np.exp(np.square(a)) c1 = np.exp(-np.square(u))*np.cos(2*a*u) c1 = c1*er #first constant term pis = np.sqrt(np.pi) c2 = 2./pis #second constant term integ = inter.quad(lambda x: np.exp(-(np.square(u)- np.square(x)))*np.sin(2*a*(u-x)), 0, u) print integ ing = c1+c2*integ[0] return ing For the Cerfc(a) function, I just use scipy.erfc

问题 I'm trying to understand the behavior of Scala for-loop implicit box/unboxing of "numerical" types. Why does the two first fail but not the rest? 1) Fails: scala> for (i:Long <- 0 to 10000000L) {} <console>:19: error: type mismatch;<br> found : Long(10000000L) required: Int for (i:Long <- 0 to 10000000L) {} ^ 2> Fails: scala> for (i <- 0 to 10000000L) {} <console>:19: error: type mismatch; found : Long(10000000L) required: Int for (i <- 0 to 10000000L) {} ^ 3) Works: scala> for (i:Long <- 0L

问题 Are there any situations where it's useful to sort numerical data alphabetically? for e.g. 111 12 2 when sorted in ascending order,give: 111 12 2 回答1: I can't think of any good reasons, and it's just going to confuse in general. 回答2: I finally thought of one. When investigating Benford's Law. Also, when the data isn't really "numerical", it's strings which just happen to consist only of digits, but which need to be lexically sorted along with other strings that might contain non-digits. But I