Introduction
------------
qml is a library for statistics, linear algebra, and optimization in kdb+.
It provides an interface between the q programming language and numerical
libraries such as LAPACK.
License
-------
qml is free software, distributed under a BSD-style license. It is provided in
the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the
implied warranties of MERCHANTABILITY and FITNESS FOR A PARTICULAR PURPOSE. See
LICENSE.txt for more details.
qml is linked against several other libraries. The copyrights and licenses for
these libraries are also listed in LICENSE.txt.
Installation
------------
To compile and install from source code, run
./configure
make
make test
make install
To install a precompiled binary, copy qml.q into the same directory as q.k, and
copy qml.dll or qml.so into the same directory as q.exe or q. Then run test.q.
Usage
-----
Load with
q)\l qml.q
All functions are in the .qml namespace. Numerical arguments are automatically
converted into floating-point. Matrixes are in the usual row-major layout (lists
of row vectors). Complex numbers are represented as pairs of their real and
imaginary parts.
q).qml.nicdf .25 .5 .975 / normal distribution quantiles
-0.6744898 0 1.959964
q).qml.mchol (1 2 1;2 5 4;1 4 6) / Cholesky factorization
1 2 1
0 1 2
0 0 1
q).qml.poly 2 -9 16 -15 / solve 2x^3-9x^2+16x-15=0
2.5
1 1.414214
1 -1.414214
q).qml.mlsq[(1 1;1 2;1 3;1 4);11 2 -3 -4] / fit line
14 -5f
q).qml.conmin[{x*y+1};{1-(x*x)+y*y};0 0] / minimize x(y+1) s.t. x^2+y^2<=1
-0.8660254 0.5
Constants and functions
-----------------------
pi pi
e e
eps smallest representable step from 1.
sin[x] sine
cos[x] cosine
tan[x] tangent
asin[x] arcsine
acos[x] arccosine
atan[x] arctangent
atan2[x;y] atan[x%y]
sinh[x] hyperbolic sine
cosh[x] hyperbolic cosine
tanh[x] hyperbolic tangent
asinh[x] hyperbolic arcsine
acosh[x] hyperbolic arccosine
atanh[x] hyperbolic arctangent
exp[x] exponential
expm1[x] exp[x]-1
log[x] logarithm
log10[x] base-10 logarithm
logb[x] extract binary exponent
log1p[x] log[1+x]
pow[a;x] exponentiation
sqrt[x] square root
cbrt[x] cube root
hypot[x;y] sqrt[pow[x;2]+pow[y;2]]
floor[x] round downward
ceil[x] round upward
fabs[x] absolute value
fmod[x;y] remainder of x%y
erf[x] error function
erfc[x] complementary error function
lgamma[x] log of absolute value of gamma function
gamma[x] gamma function
beta[x;y] beta function
pgamma[a;x] lower incomplete gamma function (a>0)
pgammac[a;x] upper incomplete gamma function (a>0)
pgammar[a;x] regularized lower incomplete gamma function (a>0)
pgammarc[a;x] regularized upper incomplete gamma function (a>0)
ipgammarc[a;p] inverse complementary regularized incomplete gamma function
(a>0,p>=.5)
pbeta[a;b;x] incomplete beta function (a,b>0)
pbetar[a;b;x] regularized incomplete beta function (a,b>0)
ipbetar[a;b;p] inverse regularized incomplete beta function (a,b>0)
j0[x] order 0 Bessel function
j1[x] order 1 Bessel function
y0[x] order 0 Bessel function of the second kind
y1[x] order 1 Bessel function of the second kind
ncdf[x] CDF of normal distribution
nicdf[p] its inverse
c2cdf[k;x] CDF of chi-squared distribution (k>=1)
c2icdf[k;p] its inverse
stcdf[k;x] CDF of Student's t-distribution (natural k)
sticdf[k;p] its inverse
fcdf[d1;d2;x] CDF of F-distribution (d1,d2>=1,x>=0)
ficdf[d1;d2;p] its inverse
gcdf[k;th;x] CDF of gamma distribution
gicdf[k;th;p] its inverse
bncdf[k;n;p] CDF of binomial distribution
bnicdf[k;n;x] its inverse for p (k<n)
pscdf[k;lambda] CDF of Poisson distribution
psicdf[k;p] its inverse for lambda
smcdf[n;e] CDF for one-sided Kolmogorov-Smirnov test
smicdf[n;e] its inverse
kcdf[x] CDF for Kolmogorov distribution
kicdf[p] its inverse (p>=1e-8)
diag[diag] make diagonal matrix
mdim[matrix] number of (rows; columns)
mdiag[matrix] extract main diagonal
mdet[matrix] determinant
mrank[matrix] rank
minv[matrix] inverse
mpinv[matrix] pseudoinverse
mm[A;B] multiply
ms[A;B] solve B=A mm X, A is triangular
mev[matrix] (eigenvalues; eigenvectors) sorted by decreasing modulus
mchol[matrix] Cholesky factorization upper matrix
mqr[matrix] QR factorization: (Q; R)
mqrp[matrix] QR factorization with column pivoting:
(Q; R; P), matrix@\:P=Q mm R
mlup[matrix] LUP factorization with row pivoting:
(L; U; P), matrix[P]=L mm U
msvd[matrix] singular value decomposition: (U; Sigma; V)
mkron[A;B] Kronecker product
poly[coef] roots of a polynomial (highest-degree coefficient first,
can be complex)
mls[A;B] solve B=A mm X
mlsx[opt;A;B] mls[] with options
`equi: equilibrate the system (default: don't)
mlsq[A;B] solve min ||B-A mm X||
mlsqx[opt;A;B] mlsq[] with options
`svd: use SVD algorithm (default: QR or LQ)
root[f;(x0;x1)] find root on interval (f(x0)f(x1)<1)
rootx[opt;f;(x0;x1)] root[] with options (as dictionary or mixed list)
`iter: max iterations (default: 100)
`tol: numerical tolerance (default: ~1e-8)
`full: full output (default: only x)
`quiet: return null on failure (default: signal)
solve[eqs;x0] solve nonlinear equations (given as functions)
solvex[opt;eqs;x0] solve[] with options
`iter: max iterations (default: 1000)
`tol: numerical tolerance (default: ~1e-8)
`full: full output (default: only x)
`quiet: return null on failure (default: signal)
`steps: RK steps per iteration (default: 1)
`rk: use RK steps only (default: RK, SLP)
`slp: use SLP steps only (default: RK, SLP)
line[f;base;x0] line search for minimum from base
linex[opt;f;base;x0] line[] with same options as rootx[]
min[f;x0] find unconstrained minimum
minx[opt;f;x0] min[] with same options as solvex[], plus
`nm: use Nelder–Mead method (default: CONMAX)
`sbplx: use Subplex method (default: CONMAX)
conmin[f;cons;x0] find constrained minimum (functions cons>=0)
conminx[opt;f;cons;x0] min[] with same options as solvex[], plus
`lincon: assume linear cons (default: nonlinear)
`cobyla: use COBYLA method (default: CONMAX)