**d2c**[control][octave/scripts/control/system/d2c.m] - Convert discrete (sub)system to a purely continuous system.
**d2_min**[optimization][octave-forge/main/optim/d2_min.m] - Newton-like minimization
**damp**[control][octave/scripts/control/base/damp.m] - Displays eigenvalues, natural frequencies and damping ratios of the eigenvalues of a matrix P or the A-matrix of a system P, respectively.
**dare**[control][octave/scripts/control/base/dare.m] - Return the solution, X of the discrete-time algebraic Riccati equation
**daspk**[calculus][octave/src/DLD-FUNCTIONS/daspk.cc] - Solve the set of differential-algebraic equations
**daspk_options**[calculus]*not implemented***dasrt**[calculus][octave/src/DLD-FUNCTIONS/dasrt.cc] - Solve the set of differential-algebraic equations
**dasrt_options**[calculus]*not implemented***dassl**[calculus][octave/src/DLD-FUNCTIONS/dassl.cc] - Solve the set of differential-algebraic equations
**dassl_options**[calculus]*not implemented***date**[system][octave/scripts/time/date.m] - Return the date as a character string in the form DD-MMM-YY.
**datenum**[system][octave-forge/main/time/datenum.m] - Returns the specified local time as a day number, with Jan 1, 0000 being day 1.
**datestr**[system][octave-forge/main/time/datestr.m] - Format the given date/time according to the format `code'.
**datetick**[system] [plotcontrol]*use*`gset xdata time; gset timefmt "%d/%m"; gset format x "%b %d"`

**datevec**[system][octave-forge/main/time/datevec.m] - Breaks the number of days since Jan 1, 0000 into a year-month-day hour-minute-second format.
**dawson**[math][octave-forge/main/gsl/gsl_sf.cc] - The Dawson integral is defined by \\exp(-x^2) \\int_0^x dt \\exp(t^2).
**dbclear**[interpreter][octave/src/debug.cc] - Delete a breakpoint in a function
**dblquad**[calculus]*not implemented***dbstatus**[interpreter][octave/src/debug.cc] - Return a vector containing the lines on which a function has breakpoints set.
**dbstop**[interpreter][octave/src/debug.cc] - Set a breakpoint in a function
**dbtype**[interpreter][octave/src/debug.cc] - List script file with line numbers.
**dbwhere**[interpreter][octave/src/debug.cc] - Show where we are in the code
**dcgain**[control][octave/scripts/control/base/dcgain.m] - Returns dc-gain matrix.
**dct**[signal][octave-forge/main/signal/dct.m] - Computes the disrete cosine transform of x.
**dct2**[signal][octave-forge/main/signal/dct2.m] - Computes the 2-D discrete cosine transform of matrix x
**dctmtx**[signal][octave-forge/main/signal/dctmtx.m] - Return the DCT transformation matrix of size n x n.
**ddemod**[communications]*not implemented***ddemodce**[communications]*not implemented***de2bi**[communications][octave-forge/main/comm/de2bi.m] - Convert a non-negative integer to bit vector.
**deal**[language][octave/scripts/general/deal.m] - Copy the input parameters into the corresponding output parameters.
**deblank**[strings][octave/scripts/strings/deblank.m] - Removes the trailing blanks and nulls from the string S.
**debug_on_error**[interpreter] [variables][octave/src/error.cc] - If the value of `debug_on_error' is nonzero, Octave will try to enter the debugger when an error is encountered.
**debug_on_interrupt**[interpreter][octave/src/sighandlers.cc] - If `debug_on_interrupt' is nonzero, Octave will try to enter debugging mode when it receives an interrupt signal (typically generated with `C-c').
**debug_on_warning**[interpreter] [variables][octave/src/error.cc] - If the value of `debug_on_warning' is nonzero, Octave will try to enter the debugger when a warning is encountered.
**debug_symtab_lookups**[interpreter][octave/src/symtab.cc] - If the value of this variable is nonzero, print debugging info when searching for symbols in the symbol tables.
**debye_1**[math][octave-forge/main/gsl/gsl_sf.cc] - The Debye functions are defined by the integral
**debye_2**[math][octave-forge/main/gsl/gsl_sf.cc] - The Debye functions are defined by the integral
**debye_3**[math][octave-forge/main/gsl/gsl_sf.cc] - The Debye functions are defined by the integral
**debye_4**[math][octave-forge/main/gsl/gsl_sf.cc] - The Debye functions are defined by the integral
**dec2base**[strings][octave/scripts/strings/dec2base.m] - Return a string of symbols in base B corresponding to the the nonnegative integer N.
**dec2bin**[strings][octave/scripts/strings/dec2bin.m] - Return a binary number corresponding the nonnegative decimal number N, as a string of ones and zeros.
**dec2hex**[strings][octave/scripts/strings/dec2hex.m] - Return the hexadecimal string corresponding to the nonnegative integer N.
**decimate**[signal][octave-forge/main/signal/decimate.m] - Downsample the signal x by a factor of q, using an order n filter of ftype 'fir' or 'iir'.
**decode**[communications][octave-forge/main/comm/decode.m] - Top level block decoder.
**deconv**[analysis][octave/scripts/polynomial/deconv.m] - Deconvolve two vectors.
**DEFAULT_EXEC_PATH**[variables][octave/src/defaults.cc] - A colon separated list of directories in which to search when executing external programs.
**DEFAULT_LOADPATH**[variables][octave/src/defaults.cc] - A colon separated list of directories in which to search for function files.
**default_save_format**[variables][octave/src/load-save.cc] - ascii
**deg2rad**[math][octave-forge/extra/mapping/deg2rad.m] - Converts angles input in degrees to the equivalent in radians.
**degree**[symbolic][octave-forge/main/symbolic/symbols.cc] - degree
**del2**[calculus][octave-forge/main/general/del2.m] - D = del2 (M) calculates the Laplace Operator
**delaunay**[analysis][octave-forge/main/geometry/delaunay.m] - The return matrix of size [n, 3] contains a set triangles which are described by the indices to the data point x and y vector.
**delaunay3**[analysis][octave-forge/main/geometry/delaunay3.m] - A matrix of size [n, 4] is returned.
**delaunayn**[analysis][octave-forge/main/geometry/delaunayn.cc] - Form the Delaunay triangulation for a set of points.
**delete**[interpreter][octave/scripts/miscellaneous/delete.m] - Delete the named file.
**demo**[interpreter] [interpreter][octave-forge/extra/testfun/demo.m] - Runs any examples associated with the function 'name'.
**DEMOcontrol**[control][octave/scripts/control/base/DEMOcontrol.m] - Octave Control Systems Toolbox demo/tutorial program.
**demodmap**[communications][octave-forge/main/comm/demodmap.m] - Demapping of an analog signal to a digital signal.
**demoquat**[analysis][octave/scripts/quaternion/demoquat.m] - Demonstrate the functions available for manipulating quaternions.
**deref**[language][octave-forge/main/general/deref.cc] - Return the N-th element of CELL.
**deriv**[optimization][octave-forge/main/optim/deriv.m] *no description***det**[matrix][octave/src/DLD-FUNCTIONS/det.cc] - Compute the determinant of A using LAPACK.
**detrend**[extra] [tsa] [analysis][octave/scripts/signal/detrend.m] - If X is a vector, `detrend (X, P)' removes the best fit of a polynomial of order P from the data X.
**dezero**[control][octave/scripts/control/obsolete/dezero.m] - Remove trailing blank entries and all zero entries from the string s.
**dfdp**[optimization][octave-forge/main/optim/dfdp.m] - numerical partial derivatives (Jacobian) df/dp for use with leasqr
**dftmtx**[signal][octave-forge/main/signal/dftmtx.m] - If N is a scalar, produces a N-by-N matrix D such that the Fourier transform of a column vector of length N is given by `dftmtx(N) * x' and the inverse Fourier transform is given by `inv(dftmtx(N)) * x'.
**dgkfdemo**[control] [control][octave/scripts/control/hinf/dgkfdemo.m] - Octave Controls toolbox demo: H2/Hinfinity options demos
**dgram**[control][octave/scripts/control/base/dgram.m] - Return controllability grammian of discrete time system
**dhbar**[plot][octave-forge/main/plot/dhbar.m] - create Bar graph
**dhinfdemo**[control] [control][octave/scripts/control/hinf/dhinfdemo.m] - Demonstrate the functions available for designining a discrete H_infinity controller.
**diag**[matrix][octave/src/data.cc] - Return a diagonal matrix with vector V on diagonal K.
**diary**[interpreter][octave/src/pager.cc] - Create a list of all commands _and_ the output they produce, mixed together just as you see them on your terminal.
**diff**[calculus][octave/scripts/general/diff.m] - If X is a vector of length N, `diff (X)' is the vector of first differences X(2) - X(1), ..., X(n) - X(n-1).
**differentiate**[symbolic][octave-forge/main/symbolic/differentiate.cc] - Return the Nth derivative of A with respect to X.
**diffpara**[signal][octave/scripts/signal/diffpara.m] - Return the estimator D for the differencing parameter of an integrated time series.
**digits**[symbolic][octave-forge/main/symbolic/symbols.cc] - Change the precision for the vpa type
**dilate**[image][octave-forge/main/image/dilate.m] - Perform a dilation morphological operation on a binary image.
**dir**[interpreter] [file][octave/scripts/miscellaneous/dir.m] - Display file listing for directory DIRECTORY.
**diric**[signal]*not implemented***discrete_cdf**[statistics][octave/scripts/statistics/distributions/discrete_cdf.m] - For each element of X, compute the cumulative distribution function (CDF) at X of a univariate discrete distribution which assumes the values in v with probabilities P.
**discrete_inv**[statistics][octave/scripts/statistics/distributions/discrete_inv.m] - For each component of X, compute the quantile (the inverse of the CDF) at X of the univariate distribution which assumes the values in V with probabilities P.
**discrete_pdf**[statistics][octave/scripts/statistics/distributions/discrete_pdf.m] - For each element of X, compute the probability density function (pDF) at X of a univariate discrete distribution which assumes the values in V with probabilities P.
**discrete_rnd**[statistics][octave/scripts/statistics/distributions/discrete_rnd.m] - Generate a row vector containing a random sample of size N from the univariate distribution which assumes the values in V with probabilities P.
**disp**[language][octave/src/pr-output.cc] - Display the value of X.
**dispatch**[interpreter][octave-forge/main/miscellaneous/dispatch.cc] - Replaces the function 'f' with a dispatch so that function 'r'
**display_fixed_operations**[Fixedpoint][octave-forge/main/fixed/fixed.cc] - Displays out a summary of the number of fixed point operations of each type that have been used.
**distance**[math][octave-forge/extra/mapping/distance.m] - Calculates the distance (in degrees) between PT1 and PT2.
**dither**[image]*not implemented***dkalman**[control][octave/scripts/control/base/dkalman.m] - Construct the linear quadratic estimator (Kalman predictor) for the discrete time system
**dlmread**[file][octave-forge/main/io/dlmread.m] - Read the matrix x from a file, with columns separated by the character sep (default is ",").
**dlmwrite**[file][octave-forge/main/io/dlmwrite.m] - write matrix to the file using delimiters (defaults to ",")
**dlqe**[control][octave/scripts/control/base/dlqe.m] - Construct the linear quadratic estimator (Kalman filter) for the discrete time system
**dlqg**[control][octave/scripts/control/obsolete/dlqg.m] - O B S O L E T E * * * D O N O T U S E!
**dlqr**[control][octave/scripts/control/base/dlqr.m] - Construct the linear quadratic regulator for the discrete time system
**dlyap**[control][octave/scripts/control/base/dlyap.m] - Solve the discrete-time Lyapunov equation
**dmod**[communications]*not implemented***dmodce**[communications]*not implemented***dmr2d**[control][octave/scripts/control/system/dmr2d.m] - convert a multirate digital system to a single rate digital system states specified by IDX, SPREFIX are sampled at TS2, all others are assumed sampled at TS1 = `sysgettsam (SYS)'.
**dmult**[matrix][octave/scripts/linear-algebra/dmult.m] - If A is a vector of length `rows (B)', return `diag (A) * B' (but computed much more efficiently).
**document**[interpreter][octave/src/variables.cc] - Set the documentation string for SYMBOL to TEXT.
**dos**[interpreter][octave-forge/main/general/dos.m] - Execute a dos command if running under Windows.
**dot**[matrix][octave/scripts/linear-algebra/dot.m] - Computes the dot product of two vectors.
**double**[strings][octave-forge/main/general/double.m] - Convert the characters of a string into its representation as a matrix of ascii codes.
**do_string_escapes**[strings][octave/src/utils.cc] - Convert special characters in STRING to their escaped forms.
**dpcmdeco**[communications]*not implemented***dpcmenco**[communications]*not implemented***dpcmopt**[communications]*not implemented***dragrect**[plotcontrol]*not implemented***drawnow**[plotcontrol][octave-forge/main/plot/drawnow.m] - This program intensionally left blank
**dre**[control][octave/scripts/control/base/dre.m] - Solve the differential Riccati equation
**dsearch**[analysis]*not implemented***dsearchn**[analysis]*not implemented***dump_prefs**[interpreter][octave/scripts/miscellaneous/dump_prefs.m] - Have Octave dump all the current user preference variables to FILE in a format that can be parsed by Octave later.
**dup2**[file][octave/src/syscalls.cc] - Duplicate a file descriptor.
**duplication_matrix**[matrix][octave/scripts/linear-algebra/duplication_matrix.m] - Return the duplication matrix Dn which is the unique n^2 by n*(n+1)/2 matrix such that Dn vech (A) = vec (A) for all symmetric n by n matrices A.
**durbinlevinson**[signal][octave/scripts/signal/durbinlevinson.m] - Perform one step of the Durbin-Levinson algorithm.
**durlev**[tsa][octave-forge/extra/tsa/durlev.m] - estimates AR(p) model parameter by solving the
**dxfwrite**[plotcontrol][octave-forge/main/plot/dxfwrite.m] - Write FILENAME as a DXF file.