simple division with integer rhs and scale

@brief Mapping 2D coordinates to 1D index in the matrix @sa getElementAt @param [in] r The row number @param [in] c The column number @param [in] col

we first calculate `1/rhs` using Newton's Method calculate by resolving f(x) = 1/x - rhs = 0 Newton's iteration: x <= (2 - x * rhs) * x (with a good i

@brief Set value of position (r, c) of the matrix. @sa getElementAt @param [in,out] mat The matrix (allocated) @param [in] pos The position marked by

@brief Get value of position (r, c) of the matrix. @sa indexAt, setElementAt @param [in] mat The matrix (allocated) @param [in] pos The position mark

set `rows` and `cols`, and allocate corresponding memory, but do NOT initialize the data WARNING: the data of `p_data` is uninitialized, so make sure

state checking and transition, `from` -> `to`

exp[x] = 1 + x + x^2/2 + x^3/6 + ...

arctan[x] = arctan[c] + arctan[(x-c)/(1+cx)], for small c (here c = 0.2) formula: arctan[x] = x - x^3/3 + x^5/5 - ...

cos[x] = 1 - x^2/2 + x^4/24 - ...

get string representation of the integer, and the length of the string must be a multiple of 4 note: there may be several leading or trailing zeros, s

sin[x] = x - x^3/6 + x^5/120 - ...

ln[x] = 1 + ln[x / e] formula: ln[1 + x] = x - x^2/2 + x^3/3 - ...

pi = 16 * arctan[1/5] - 4 * arctan[1/239]