onlineregression14:   Multiple nonlinear regression   ⇒   y = f(x1, x2) Formulas u = log(x1)           v = log(x2)           w = log(y) t1 = n∑wv - ∑w∑v           t2 = n∑u∑v - ∑u∑v          t3 = n∑v2 - (∑v)2 t4 = n∑wu - ∑w∑u           t5 = n∑uv - ∑u∑v           t6 = n∑u2 - (∑u)2 t7 = n∑v2 - (∑v)2 β1 = (t1*t2 - t3*t4)/(t5*t5 - t6*t7)          β2 = (t4 - β1*t6)/t2 α = (∑w - β1∑u - β2∑v)/n          a = 10[(∑w - β1∑u - β2∑v)/n] b1 = β1          b2 = β2          y = a x1b1 x2b2 Reference Ponce, V. M. 1989. Engineering Hydrology, Principles and Practices. Prentice Hall, page 241-243. Example INPUT DATA: Enter array size n:      Enter corresponding values of arrays y, x1 and x2 (separate each value with a comma; maximum string length is 300 characters). y:      x1:      x2:      ECHO OF INPUT: Warning: Undefined variable $number in /var/www/html/ponce/onlineregression14.php on line 274 n =   Warning: Undefined variable $number in /var/www/html/ponce/onlineregression14.php on line 276 Warning: Undefined variable $j in /var/www/html/ponce/onlineregression14.php on line 282 Warning: Undefined variable $yvar in /var/www/html/ponce/onlineregression14.php on line 283 Warning: Trying to access array offset on null in /var/www/html/ponce/onlineregression14.php on line 283 y(1) =  .    Warning: Undefined variable $number in /var/www/html/ponce/onlineregression14.php on line 286 Warning: Undefined variable $j in /var/www/html/ponce/onlineregression14.php on line 292 Warning: Undefined variable $x1var in /var/www/html/ponce/onlineregression14.php on line 293 Warning: Trying to access array offset on null in /var/www/html/ponce/onlineregression14.php on line 293 x1(1) =  .    Warning: Undefined variable $number in /var/www/html/ponce/onlineregression14.php on line 296 Warning: Undefined variable $j in /var/www/html/ponce/onlineregression14.php on line 302 Warning: Undefined variable $x2var in /var/www/html/ponce/onlineregression14.php on line 303 Warning: Trying to access array offset on null in /var/www/html/ponce/onlineregression14.php on line 303 x2(1) =  .    OUTPUT: a = Warning: Undefined variable $acoef in /var/www/html/ponce/onlineregression14.php on line 311 Deprecated: substr(): Passing null to parameter #1 ($string) of type string is deprecated in /var/www/html/ponce/onlineregression14.php on line 311            b1 = Warning: Undefined variable $beta1 in /var/www/html/ponce/onlineregression14.php on line 312 Deprecated: substr(): Passing null to parameter #1 ($string) of type string is deprecated in /var/www/html/ponce/onlineregression14.php on line 312            b2 = Warning: Undefined variable $beta2 in /var/www/html/ponce/onlineregression14.php on line 313 Deprecated: substr(): Passing null to parameter #1 ($string) of type string is deprecated in /var/www/html/ponce/onlineregression14.php on line 313                      y = Warning: Undefined variable $acoef in /var/www/html/ponce/onlineregression14.php on line 314 Deprecated: substr(): Passing null to parameter #1 ($string) of type string is deprecated in /var/www/html/ponce/onlineregression14.php on line 314 x1 Warning: Undefined variable $beta1 in /var/www/html/ponce/onlineregression14.php on line 314 Deprecated: substr(): Passing null to parameter #1 ($string) of type string is deprecated in /var/www/html/ponce/onlineregression14.php on line 314 x2 Warning: Undefined variable $beta2 in /var/www/html/ponce/onlineregression14.php on line 314 Deprecated: substr(): Passing null to parameter #1 ($string) of type string is deprecated in /var/www/html/ponce/onlineregression14.php on line 314   Your request was processed at  04:15:41 am on April 3rd, 2025   [ 250403  04:15:41 ]. Thank you for running onlineregression14.   Please call again.   [161109]

 

online calc
normal depth	critical depth	normal and critical depth		discharge in channel	critical slope
normal depth in culvert	critical depth in culvert	discharge in culvert		discharge sluice	discharge weir
M1 wsprofile	M2 wsprofile	M3 wsprofile	S1 wsprofile	S2 wsprofile	S3 wsprofile
C1 wsprofile	H2 wsprofile	A2 wsprofile	C3 wsprofile	H3 wsprofile	A3 wsprofile
sequent depth HJ	energy loss HJ	initial sequent HJ	efficiency HJ	critical width constriction
ogee spillway	Hazen-Williams	parallel pipes	three reservoirs	tractive force
V-notch weir	V-notch partially contracted	Cipolletti weir	Rectangular weir	Standard contracted rectangular weir	Standard suppressed rectangular weir
Froude number		Vedernikov number		Limiting contracting ratio
Creager	rational	slope-area	linear reservoir	storage indication 1	storage indication 2
Muskingum	Muskingum-Cunge	time-area	Clark UH	Cascade of linear reservoirs
USGS Methods for magnitude of floods in California	Kinematic wave applicability	Diffusion wave applicability	Clark's unit hydrography compared to Ponce's version	Correlation coefficient of a joint probability distribution	Storage volume of a detention basin
Blaney-Criddle	Penman	Penman-Monteith reference crop	Thornthwaite	Priestley-Taylor	Penman-Monteith ecosystems
Gumbel	Gumbel 2	Log Pearson	Log Pearson 2	TR-55 graphical	curve number
Overland flow using the diffusion wave method	Dynamic hydraulic diffusivity	convolution	S-hydrograph	time of concentration	water balance
UH cascade	dimensionless UH cascade		general UH cascade	series UH cascade	all series UH cascade
one-predictor linear	one-predictor nonlinear	two-predictor linear	two-predictor nonlinear	hyperbolic regression
fall velocity	Lane & Koelzer	USLE	USLE2	Dendy-Bolton	Shields
Duboys	Meyer-Peter	Colby 1957	Colby	reservoir design life	Equilibrium channel top width using the Lane et al. theory
Modified Einstein Procedure		bridge scour using Melville equation
DO sag	DO sag analysis		Oxygenation	Salinity (EC to TDS)