ndvi calculation

Turn from: http://www.cnblogs.com/haoyul/p/6910679.html For a long time did not write code, recently took the calculation of triangular mesh surface Gauss curvature practiced practicing, and realized the Gaussian curvature visualization, reviewed a little differential geometry knowledge. Feel sometimes still want to write the code, debugging and running, combined with the test results, in order to have a deeper understanding of the corresponding know

Calculating the time difference in PHP is sometimes a hassle! However, I believe that any language, as long as the grip of the regulation rate can find a way, is absolutely rotten to the magic. Work often to carry out the date calculation, the following summary of several work summed up the experience. Make a note lest you forget it later! 1. First calculation time period difference (can be minutes, seconds

Ken_len represents the number of bytes used by the index, based on this value, it is possible to determine the index usage, especially when combining indexes, to determine whether all the indexed fields are queried.Key_len shows the index length required by the conditional retrieval clause, but the index used by the ORDER by and the GROUP by clause does not count toward the key_len statistic value;About the calculation rules for Key_len:• When the ind

definition of time complexity in general, the number of times the basic operation is repeated in the algorithm is a function of the problem size n, denoted by T (n), if there is an auxiliary function f (n), So that when n approaches infinity, the limit value of T (n)/f (n) is a constant that is not equal to zero, then f (n) is the same order of magnitude function of T (N). As T (n) =o (f (n)), called O (f (n)) is the progressive time complexity of the algorithm (O is the order of magnitude )

Label:BackgroundIn the MySQL master and standby environment, the main standby synchronization process is as follows, the main library update generates Binlog, the standby IO line pulls take the main library binlog generate relay log. The standby SQL thread executes the relay log to maintain synchronization with the main library. In theory, when the main library is updated, there is a delay in the standby, and the delay time is the standby execution time + network transmission time is t4-t2. So

Yesterday, bitcoin.org in charge of Cobra issued an open letter angry godless bit continent, require Bitcoin users to modify the POW algorithm, using Pow+pos hybrid system, and select those convenient to build Asics algorithm.Then, the bit Continental CEO Wu Bogey Cold in the Twitter response said "too cool." When you do this, Bitcoin's share in the cryptocurrency market will probably fall below 10%. Good luck! ”。In the open letter, Cobra expressed the following views:1. Bitcoin's central featur

as followsThe concept of dielectric constant (DK)The electrical capacity of CX with the presence of a dielectric between the capacitor plates is the permittivity of the same shape and size of the vacuum capacitance co:ε= cx/co =ε '-ε 'The concept of Prepreg/corePP is a medium material, composed of glass fiber and epoxy resin, core is actually the type of PP media, but he is covered with copper foil on both sides, and PP did not.calculation of characteristic impedance of transmission lineFirst,

Cost = product cost + period cost Product cost calculation includesDirect Material fee, Direct labor costsAndManufacturing fee.WhileManufacturing feeByIndirect variable manufacturing fee(Such as fuel and machine boring) andIndirect fixed manufacturing fee(Directly related to production, such as wages and office repair fees. The period fee is the cost of the company's management. Their results are as follows: I. Various Cost

The priority of the selector is related to the style applied by the element. The specification (http://www.w3.org/TR/2009/CR-CSS2-20090908/cascade.html#specificity) in CSS2.1 is described as follows: Connect the four numbers in a-B-c-d (in a numeric system with a large number) to form the priority of the selector. In the latest Selector Level 3 specification:Connect the three numbers in a-B-c (in a numeric system with a large number) to form the priority of the selector. For details about style

Algorithm training expression calculation time limit: 1.0s memory limit: 256.0MB Problem Description Enter a valid expression that contains only the plus and minus and parentheses, to find the value of the Expression. where except for the integer Division. Enter a line in the format that contains an Expression. The output format outputs the value of this Expression. Sample input 1-2+3* (4-5) sample output-4 data size and contract expression length not

in a report project, data calculation methods for some reports change frequently. For example, the real wages of an enterprise employee are calculated by the performance score, the algorithm changes frequently, and the old algorithm needs to be replaced with the new algorithm without altering the other code. If the computation is implemented in Java, it is possible to implement dynamic hook-up calculation m

about TensorFlow Computing model TensorFlow's programming differs greatly from the way I used to approach programming. Previous programming, whether the compiler type of language or scripting language, is a step-by-step, variable calculation, you will get results, such as c=a+b, when the execution of the statement, you will get the value of C. But TensorFlow is not, it first to programmatically, build a calculati