DCTIMESTEP(1)                                                    DCTIMESTEP(1)



NNAAMMEE
       dctimestep - compute annual simulation time-step via matrix multiplica-
       tion

SSYYNNOOPPSSIISS
       ddccttiimmeesstteepp VVssppeecc TTbbssddff..xxmmll DDmmaatt..ddaatt [ ttrreeggvveecc ]

DDEESSCCRRIIPPTTIIOONN
       _D_c_t_i_m_e_s_t_e_p takes four input files, forming a  matrix  expression.   The
       first argument is the View matrix file that specifies how window output
       directions are related to some set of measured values, such as an array
       of  illuminance  points  or images.  This matrix is usually computed by
       _r_t_c_o_n_t_r_i_b_(_1_) for a particular set of windows or skylight openings.  The
       second  argument is the window transmission matrix, or BSDF, given as a
       standard XML description.  The third argument is  the  Daylight  matrix
       file  that  defines  how  sky patches relate to input directions on the
       same opening.  This  is  usually  computed  using  _g_e_n_k_l_e_m_s_a_m_p_(_1_)  with
       _r_t_c_o_n_t_r_i_b  in  a  separate run for each window or skylight orientation.
       The final input is the sky contribution  vector,  usually  computed  by
       _g_e_n_s_k_y_v_e_c_(_1_)_,  which  may  be  passed on the standard input.  This data
       must be in ASCII format, whereas the View  and  Daylight  matrices  are
       more efficiently represented as binary float data if machine byte-order
       is not an issue.

       Sent to the standard output of _d_c_t_i_m_e_s_t_e_p is either an ASCII color vec-
       tor  with as many RGB triplets as there are rows in the View matrix, or
       a combined _R_a_d_i_a_n_c_e picture.  Which output is produced depends  on  the
       _V_s_p_e_c  argument.  A regular file name will be loaded and interpreted as
       a matrix to generate a color results vector.  A file specification con-
       taining  a '%d' format string will be interpreted as a list of _R_a_d_i_a_n_c_e
       component pictures, which will be summed according to the computed vec-
       tor.

EEXXAAMMPPLLEESS
       To  compute a set of illuminance contributions for Window 1 on the Win-
       ter solstice at 2pm:

         gensky 12 21 14 | genskyvec | dctimestep IllPts.vmx Blinds20.xml Win-
         dow1.dmx > Ill_12-21-14.dat

       To compute Window2's contribution to an interior view at 12 noon on the
       Summer solstice:

         gensky 6 21 12 | genskyvec  |  dctimestep  view%03d.hdr  Blinds30.xml
         Window2.dmx > view_6-21-12.hdr

AAUUTTHHOORR
       Greg Ward

SSEEEE AALLSSOO
       genklemsamp(1),   genskyvec(1),  mkillum(1),  rtcontrib(1),  rtrace(1),
       vwrays(1)



RADIANCE                           12/09/09                      DCTIMESTEP(1)
